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chris24
01-10-2011, 10:58 AM
Been getting used to my new Modulating Condensing boiler for a week. Still not sure it is set up right. The system is as such...
Burnham Alpine 80 MBH 5:1 turndown w/ Taco 010 Boiler pump
Triangle Tube Smart 40 Tank-in-tank Indirect Hot Water (36gal DHW under 6gal boiler H2O)
Taco SR503 Zone controller w/ 3) Taco 007 zone circulators feeding IHW and downstairs/upstairs zones with baseboard convectors & Honeywell RTH 6000 T-stats

At first unit was short cycling (4 mins. on / 7 mins. off) before adjusting the ODR curve. Temps have been pretty mild here in PHL since New Years but I think I am pretty close. Currently set with “Outdoor low air temp” = 14*f , “High od temp” = 68*f, “Boiler low temp” = 100*f, “Boiler high temp” = 150*f. The ODR calculated setpoint is 134*f at 32*f outside. I am now getting about 7 min runs with 4 mins. off. Setpoint differences are at the factory default of 2*f above, 10*f below, although sometimes I will noticed on the status window that it will display 20*f below and then revert back to10. Can these be changed to help with the cycling? The system is modulating at about 40% when it is about 32*f outside, supply at 131*f, return at 120*f so I am condensing (Max. Eff. On” displayed). House is very comfortable, if not warm, at 68F.

I have put my t-stats on “Hold” and am not using a 3*f setback at night because the other day it took @ 4 hrs of constant running to recover, which I feel is a little long, and my daughter woke up to a cold house so some adjustment are still required. Even with these settings I notice the boiler is cycling but I think this is due to the thermostats as I can see the zone LED’s toggling. I have verified they are set up correctly with function code 1 = 2 “heating Only”, function code 5 = 3 “hot water system” . I have turned off the “Smart Responce” control thinking this was causing the cycling. There does not seem to be any “anticipator” or “swing” settings on these thermostats.

What are the best settings to start with for the IHW. I currently have DHW priority with a setpoint temp of 160*f. Is this too high? What should the tank T-stat be set at? I can always adjust the mixing valve to correct spigot temps. (We take mainly showers do not have large HW demands). A funny thing I did noticed was that when I have a Priority DHW call at the furnace that my zone pumps are still running. I know is not correct as they will be pushing 160* water in to the zones. The installers wired the DHW pump to the boiler contacts as opposed to the Taco zone controller. Is there a switch on the SR503 that needs to be set? Can I run a H2O T-stat wire in parallel to the zone controller so it knows when the DHW priority call is made?

Still not sure if the whole system is optimally piped, but that will be another post.

mage182
02-17-2011, 01:44 PM
I'll chime in on what I can here. I'm in the same situation. Just had my Alpine (150 model) installed last week with a Burnham 50 gal IHW tank.

I haven't played with the numbers and the ODR. But it was 36 degrees the other day and it was running at 135 which is close to what you have.

I have my DHW setpoint at 180 (default). I have no mixing valve installed. As per the manual, when the tank calls for heat the only pump that should be running is the IHW pump (no zone pumps, no boiler pump, no system pump). So I have set the options to that. The DHW should be wired to the boiler because if it is wired to the taco box the boiler would not be able to tell the difference between a zone and the tank and respect to temps. The boiler computer controls that.

My boiler keeps cycling up and down when heating the water. It heats up to ~180 and then runs until the temp drops. Then cycles up again. I'm reading that it's supposed to do this but still seems kind of odd.

I'm more positive on the piping in my system, I just wish the book was more robust in helping to set the system up. I'm doing it on my own and it's a bit confusing.

jadnashua
02-17-2011, 01:58 PM
180-degrees in the indirect is WAY too hot without a tempering valve installed, and where I live, would never pass code. To get it that hot, the boiler needs to burn hotter, too, which decreases efficiency.

mage182
02-18-2011, 05:58 AM
I just left it to what it was set at from the factory.

What is the recommended setting for that? My only concern is that if I cut the setpoint temp to 160, the boiler will have to cycle more times before the water in the tank reaches the requested temp (130-140). During that period, no heat for the house is being produced.

jadnashua
02-18-2011, 12:41 PM
You could set the indirect to whatever temp you want, BUT, please put a tempering valve on its outlet to prevent that excessively hot water from making it to your shower or taps. It would quickly scald an unsuspecting visitor and maybe you as well. The higher the storage temperature, the greater stored energy you have, which means you have more hot water available. But, it also means more standby losses since the delta T between the stored water and the room is higher.

The boiler should not cycle on/off when the indirect calls for heat. The return water should end up cool enough so that it stays on until the tank is reheated. There may be some confusion here...having the boiler run up to 180-degrees (or even higher) while the indirect is calling for heat is normal, as you want it to reheat as fast as possible, and minimize the time the house is not being heated because of the priority zone arrangement. It sounded like you were trying to get the indirect up to 180-degrees, which is way too hot. 140-degrees (with a tempering valve) is fairly common setpoint for an indirect.

If the burner is cycling on/off too much, and it isn't modulating down to its lowest settings, then something needs to be tweaked. If it is burning at the minimum, and is then cycling most of the time, regardless of the weather, it is too big. Ideally, the boiler would run constantly at just the right supply temp to just heat the house, and adjust the boiler water temp up or down to maintain that 'just right' temp while the burner stays on. Short cycling is a sign of oversize or improper setup.

tk03
02-18-2011, 04:04 PM
Mage182,
The tank has it's own control to control the tank temp but the boiler water temp when making hot water is usually set to 180f. The greater the temperature difference between the tank coil and the tank water gives the greatest transfer.

Chris24,
The Alpine manual shows a wiring diagram to prioritize the heating zone pumps when making hot water.
The indirect is supposed to be wired to the boiler along with the indirect pump. Than program the pumps to run as needed.

To all,
The way to set your ODR curves is to measure the lineal feet of element of radiation (copper tube type) or calculate sq ft of radiation. Which ever you do you divide that into the heat loss your contractor supplied. Hopefully they did two. One at the design outdoor temp and one at 60f. Compare this to the radiation charts. This gives you the min and maximum water temperatures. The minimum and maximum air temps are 60f and your area outdoor design temp. The minimum boiler temp is dependent on the type of radiation you have.

As far as the indirect water heater goes determine what the manufactured btu input is rated at. If it is less than the boiler size than turn the fan speed down to the input required. The Burnham Alliance 50 input is 110,000. The ALP150 boiler is 150k input. Turn the DHW fan speed down to about 100k input to match what the tank needs.

mage182
02-22-2011, 06:04 AM
The boiler should not cycle on/off when the indirect calls for heat. The return water should end up cool enough so that it stays on until the tank is reheated. There may be some confusion here...having the boiler run up to 180-degrees (or even higher) while the indirect is calling for heat is normal, as you want it to reheat as fast as possible, and minimize the time the house is not being heated because of the priority zone arrangement. It sounded like you were trying to get the indirect up to 180-degrees, which is way too hot. 140-degrees (with a tempering valve) is fairly common setpoint for an indirect.

If the burner is cycling on/off too much, and it isn't modulating down to its lowest settings, then something needs to be tweaked. If it is burning at the minimum, and is then cycling most of the time, regardless of the weather, it is too big. Ideally, the boiler would run constantly at just the right supply temp to just heat the house, and adjust the boiler water temp up or down to maintain that 'just right' temp while the burner stays on. Short cycling is a sign of oversize or improper setup.

Perhaps it was only cycling on and off because I had the tank heating up for the first time? The water in the tank was about 40 degrees. I only set the setpoint on the tank to 135. The boiler was heating up to 180, then shutting down while the indirect pump was still running. Once the water made it down to ~112 the boiler would come back on. As of right now it's hard to test for regular usage because I'm not living at the house. My main goal is to get the heat working so I can finishing spackling and start painting. Maybe I'll just leave the indirect off for now since I don't need hot water and just work with the heat.

I know the boiler and tank are a bit over sized. But I had to do it that way to accommodate the expansion I'm planning on in the next few years (another bathroom, another heating zone, a larger kitchen). I don't think it's really short cycling, but I have the feeling someone who is trained on the unit would be able to tweak it beyond what I've done. I'm just going by what the book says.

mage182
02-22-2011, 06:22 AM
To all,
The way to set your ODR curves is to measure the lineal feet of element of radiation (copper tube type) or calculate sq ft of radiation. Which ever you do you divide that into the heat loss your contractor supplied. Hopefully they did two. One at the design outdoor temp and one at 60f. Compare this to the radiation charts. This gives you the min and maximum water temperatures. The minimum and maximum air temps are 60f and your area outdoor design temp. The minimum boiler temp is dependent on the type of radiation you have.

As far as the indirect water heater goes determine what the manufactured btu input is rated at. If it is less than the boiler size than turn the fan speed down to the input required. The Burnham Alliance 50 input is 110,000. The ALP150 boiler is 150k input. Turn the DHW fan speed down to about 100k input to match what the tank needs.

After going through two plumbers and finishing the install myself, heat loss calcs aren't something I have readily on hand. I have the calculations used to determine how many feet of baseboard to put in each room, as well as the charts for the baseboard I got. Using that how do I determine the min/max temps?

Are you referring to the fan rpm settings in the contractor setup? If memory serves it lets you set the fan speed for each application. How do I know what speed matches a ~100k input?

Dana
02-22-2011, 12:38 PM
After going through two plumbers and finishing the install myself, heat loss calcs aren't something I have readily on hand. I have the calculations used to determine how many feet of baseboard to put in each room, as well as the charts for the baseboard I got. Using that how do I determine the min/max temps?

Are you referring to the fan rpm settings in the contractor setup? If memory serves it lets you set the fan speed for each application. How do I know what speed matches a ~100k input?

Forget about setback thermostats, and to hell with the heat loss calcs and radiation charts- use the boiler's ODR programming to empirically determine & track the heat load. Using setback thermostats bumps the ODR curve up during the recovery, losing more more in foregone condensing efficiency and cycling loss than you were gaining by using the setback (unless you live in the worlds leakiest house.)

The way to get the most out of a mod con is to keep cranking back the design temp until it stays on continuously, not 7 on/4 off or anything close. If you can't get 20+ minute burns out of it at 35F outdoor temps at min-mod it means the boiler is too big, or you have the curve set too high.

As a practical matter it's tough to get consistent results out of fin-tube baseboard at boiler output temps below ~120F, so you might start there and work your way up. I haven't looked too deeply at the ODR programming details for the Alpine, but set min-temp to 120F for truncating the low end of the curve at a fixed temp, and start out maybe 125F or 130F for the space heating setpoint temp, and bump it up 5F at a time until it seems to keep up over a few days of real heat load, then back off a degree or two (if it allows that fine a tuning.)

A lot of homes with fin tube baseboard were designed for 160-180F water under design conditions (coldest 2% of the hours in a heating season) using generous margins on the heat loss estimate &/, or were later tightened up, insulation added, windows upgraded etc, and could be heated with 130F-140F water all season long. Don't be stunned if you can run it all season long at a fixed temp at 120F either, if you've undergone a lot of upgrades. Heat loss calcs (even better ones) are often 20% ahead of reality, and old schooler "...lessee 35BTU/foot time 2200 square feet..." methods of estimation were often 100% or more ahead of reality even BEFORE the building weatherization was updated. When 100% overdesigned for 180F water, baseboard systems typically deliver design-day heat at ~135F (look at your baseboard output charts for verification- they may stop at 140F on the low end, so you may have to interpolate downward.)

If even more overdesigned than that, you don't end up with much "curve" before bottoming out at 120F, but you'd need real radiators (or cast-iron baseboard) to get any curve to track well much below that.

Dana
02-22-2011, 02:25 PM
It occurs to me that the other reason you can end up with short-cycling like that is when the radiation can't deliver the amount of heat at that temp, and raising the temp slightly could lenghten the burn, trading condensing efficiency against cycling losses. If there's a min-modulation mode in the setup that ignores the ODR, try that out. In a call for heat it would start out cold and the temps would rise eventually settling at the temp at which the radiation output is identical to the boiler output until the thermostat is statisfied. It should able to keep up at lower heat loads and still maximize the condensing efficiency at low load, but probably won't keep up mid-winter. Mid-mod out on an Alpine 80 is ~14-15KBTU/hr which is about what my place would need at 30F. If it has that type of mode setting, that would also provide a real measurement of the output temperature crossover point below which the system is prone to short-cycling, and you may want to set that as your min temp provided it's low enough that it's condensing.


If it settles in above a condensing temp, you can add length to the burns by adding thermal mass. Baseboards are inherently low-mass so if boiler output at min-mod is overshooting what the baseboard can deliver for a condensing temp, an electric hot water heater plumbed in series with the baseboard loop (but not wired up to heat the water) can be a relatively low-cost solution to getting the burn lengths over 10 minutes. Every startup cycle puts wear on the boiler and cuts into efficiency- adding mass you may end up with about the same overall duty cycle, but it dramatically reduces the number of cycles per hour/day.

mage182
02-23-2011, 06:37 AM
What you are saying about the 120F starting point makes sense. But I already know the boiler is over sized for my house. I bought it bigger to allow for future expansion. This install is during the process of a complete renovation. All windows are new, everything is insulated, and it's a conversion from oil FHA to gas hydronic so all the baseboards are installed brand new.

Is there a way I can dial settings back to allow for the oversizing of the boiler at this point? I'd like to try that as well as changing the ODR settings.

I'm not a plumber and this keeps getting more and more complicated. I wish I could find someone in my area that knows about the Alpine specifically and could come tweak the system. I'm not living in the house and I still have lots of work to do to get it done so I don't really have time to hang out there for hours messing with the system hoping it's right.

jadnashua
02-23-2011, 11:31 AM
As Dana said, if you put a buffer tank (say an electric WH, but just don't hook it up to electricity), it will force the boiler to work longer to keep that extra volume of water hot for use in your heating system. The key point is that it appears that that boiler's ability to modulate is such that the lowest output is still too big for your house. Some boilers can modulate from as little as about 20% of their max (or even a little less). Do not know the range of modulation on the Alpine model. One sized such that the minimum would have worked might have been a better choice.

mage182
02-23-2011, 12:12 PM
I don't think I'll be needing a buffer tank. I just need to find out how to set up all the variables so that the boiler cycles correctly based on the lowest temperature and proper fan speed. The problem is how to do that. The number of variables is large and I'm not trained on this sort of thing. It's easy to talk about principles and how to get the system to work at max efficiency, but when it comes to actually inputting everything into the computer, that's where I get lost.

jadnashua
02-23-2011, 02:52 PM
If the boiler is too big for the load, it will reach its high temp point and shut off...no way around it since if it continued to fire, it would get too hot, produce steam and really make a mess of things. So, to get a decent burn cycle, you need to give it a bigger load...a buffer tank will do that and produce greater economy and increase the longevity of the boiler. No setting of the curves will overcome the fact that the thing is too big.

Dana
02-23-2011, 03:13 PM
What you are saying about the 120F starting point makes sense. But I already know the boiler is over sized for my house. I bought it bigger to allow for future expansion. This install is during the process of a complete renovation. All windows are new, everything is insulated, and it's a conversion from oil FHA to gas hydronic so all the baseboards are installed brand new.

Is there a way I can dial settings back to allow for the oversizing of the boiler at this point? I'd like to try that as well as changing the ODR settings.

I'm not a plumber and this keeps getting more and more complicated. I wish I could find someone in my area that knows about the Alpine specifically and could come tweak the system. I'm not living in the house and I still have lots of work to do to get it done so I don't really have time to hang out there for hours messing with the system hoping it's right.

Oversizing isn't usually as big an issue with mod-cons until/unless it's RIDICULOUSLY oversized. (You didn't buy the Alpine -150 or -285, I hope? The -80 and -105 would be enough boiler for about 90% of the single-family homes in NY.) The min-modulated input of the Alpine 80 is ~16KBTU/hr, max is ~80K. Almost any house but a superinsulated house will have at least a 15k load at 20-25F outside temps.

You DO need to run it a modulation level & temperature where the radiation can give up that amount heat to the house though. You can set it to 120F out and if the baseboards are short enough that they only deliver 8-9K to the house at that temp range it'll short-cycle, even at minimum fire. If it's running higher than min with a small delta-T between output and return, with a ball-valve in the loop you could carefully reduce the flow until it's running at the minimum modulation at the output temp you've set.

Some boilers can be programmed to run at min-mod only as a test to determine the temperature at which it'll short-cycle with the given flow rate, and it appears the Alpine does too (see figure 38, upper left : http://s3.pexsupply.com/manuals/1249544660434/Alpine_I&O_Manual_101602-01_Feb08.pdf ) If you leave the boiler off for a good half hour, then start it in min-modulation mode, the temperature it reaches after about 10-12 minutes is pretty much the minimum temp below which it would otherwise short-cycle, so set your reset curve minimums accordingly. (The note says that it automatically reverts to modulation mode after 15 minutes if you put it in the min-mod test mode.) If the return water temp is out of the condensing range (well above 120F on the return), then it's probably worth adding a tank to buffer it so that it can be run at lower temp without short cycling. This is a 15 minute test- you can tweak the rest of the curve later after you've moved in, but stopping the short-cycling saves a lot of wear & tear on the boiler.

Since this is a new heating system design, hopefully the designer maxed out the baseboard length to ensure that it can deliver design-day heat in the condensing zone most of the time, and without short-cycling issues. Baseboard is so CHEAP that it should be a crime to design a system that needs 180F on design-day, since for less than $20/foot it can be lengthened 50% and be able to deliver it at 140F, with 120F return. Of course it's always possible to run out of wall-length, at which point flat-panel radiators start looking more attractive despite the higher price. (They're definitely more comfortable than fin-tube baseboard, comparable or better comfort than cast-iron baseboard.)

mage182
02-24-2011, 06:03 AM
Oversizing isn't usually as big an issue with mod-cons until/unless it's RIDICULOUSLY oversized. (You didn't buy the Alpine -150 or -285, I hope? The -80 and -105 would be enough boiler for about 90% of the single-family homes in NY.) The min-modulated input of the Alpine 80 is ~16KBTU/hr, max is ~80K. Almost any house but a superinsulated house will have at least a 15k load at 20-25F outside temps.

You DO need to run it a modulation level & temperature where the radiation can give up that amount heat to the house though. You can set it to 120F out and if the baseboards are short enough that they only deliver 8-9K to the house at that temp range it'll short-cycle, even at minimum fire. If it's running higher than min with a small delta-T between output and return, with a ball-valve in the loop you could carefully reduce the flow until it's running at the minimum modulation at the output temp you've set.

Some boilers can be programmed to run at min-mod only as a test to determine the temperature at which it'll short-cycle with the given flow rate, and it appears the Alpine does too (see figure 38, upper left : http://s3.pexsupply.com/manuals/1249544660434/Alpine_I&O_Manual_101602-01_Feb08.pdf ) If you leave the boiler off for a good half hour, then start it in min-modulation mode, the temperature it reaches after about 10-12 minutes is pretty much the minimum temp below which it would otherwise short-cycle, so set your reset curve minimums accordingly. (The note says that it automatically reverts to modulation mode after 15 minutes if you put it in the min-mod test mode.) If the return water temp is out of the condensing range (well above 120F on the return), then it's probably worth adding a tank to buffer it so that it can be run at lower temp without short cycling. This is a 15 minute test- you can tweak the rest of the curve later after you've moved in, but stopping the short-cycling saves a lot of wear & tear on the boiler.

Since this is a new heating system design, hopefully the designer maxed out the baseboard length to ensure that it can deliver design-day heat in the condensing zone most of the time, and without short-cycling issues. Baseboard is so CHEAP that it should be a crime to design a system that needs 180F on design-day, since for less than $20/foot it can be lengthened 50% and be able to deliver it at 140F, with 120F return. Of course it's always possible to run out of wall-length, at which point flat-panel radiators start looking more attractive despite the higher price. (They're definitely more comfortable than fin-tube baseboard, comparable or better comfort than cast-iron baseboard.)


I have the 150 model. No one said anything either way when we selected it. After 5 months of reading I know the 105 would have been sufficient but there really isn't anything that can be done about that now.

Is the baseboard length maxed out? Not at all. I did put in longer lengths than were specd and used multipak-80 Slant Fins instead of Fine-30. If absolutely necessary, all of the baseboard lengths could be extended rather easily and I would rather do that than add a buffer tank.

This project has been the only real issue throughout the entire renovation. It seems more and more that it's just another case of unqualified contractors trying to accomplish a task they are not capable if doing. I'm going to have to continue to look for someone who is educated specifically in the Alpine boiler and can come in to look at the system, tweak whatever needs to be configured, and give recommendations if anything else needs to be changed. This was supposed to be an exercise in energy efficient home heating, not installing an over sized boiler that negates any benefit of it's efficiency possibilities.

Dana
02-24-2011, 12:57 PM
Min-mod on the Alpine 150 is 30KBTU/hr in, or 27-28K out, which is about what the heat load is on my antique ~2000' house (+ ~1500 of unfinished basement) is in Worcester MA when it's +4F out (the 97.5% outside design temperature in my neighborhood). This place still has plenty of tightening & insulating left to do, with antique double-hungs + storms for most of the glazing, and full-dimension 2x4 studwalls with dense-packed cellulose in most but not all of it, and ~R20 of rigid board insulation over 90% of the wall area of the basement, but still with known as-yet untreated gaps in the attic insulation (probably averages R15 when you count the gaps.) If your rehab & windows are a lot tighter & higher-R than mine, odds are you're at a similar or lower heat load unless you have a bigger house, or you have central/northern NY design temp , not L.I. or Westchester type design temps. (What's your zip code? Description of the house, insulation, siding attic, size???)

That said, if you can get enough baseboard to deliver design-day heat at 120-130F output temps it'll still run VERY efficiently if it's burns are consisitently longer than 10 minutes. If a room by room heat loss had been done to determine the baseboard lengths you could just add a proportional amount to each length if running the min-mod test results in output temps over 140F (or more importantly, return water temps over 120F, which is the ~90% combustion efficiency zone.) Or, armed with your min-mod test numbers and the room by room heat loss and baseboard length numbers you could look for a hydronic heating designer (not a plumber or plumbing & heating installer, though sometimes they're the same person/company), and see where it's best tweaked from a design point of view.

In very rough terms the multipak 80 (http://slantfin.com/documents/677.pdf) delivers on the order of 250-300BTU/foot with 130-140F output, 110-120F returns, which means you'd need something like 100' total to be able to deliver the minimum modulated output with 130F water. If you have at least that much, you can get there from here tweaking the flow (with a ball valve or multi-speed pump) and min temp programming. If it turns out you need more heat than min mod at design outdoor temps you can bump it up, but otherwise setting the ODR curve to about the same as the minimum temp (if it'll let you), will get it to run in on/off mode at or near the minimum fire, and the hysteresis of the wall thermostat along with thermal mass of the house will determine the actual minimum burn length. The lengths of the burns will increase with the actual heat load, and could be hours long when it's very cold out, even if it's only 10-15minutes every couple of hours when it's 50F outside. Getting it to fewer than 20 burns/day would be good for efficiency, getting it to under 10/day would be GREAT. A "right sized" mod-con with outdoor reset can be tweaked to deliver fewer than that when serving a single-zone system, but it's not substantially more efficient when the cycle numbers are that low.

When all else fails, 20-40 gallons of buffer tank in series cures a world of cycling ills. 100' of 3/4" pipe is only a couple of gallons- there's not much thermal mass there. Adding buffer tanks to low-mass systems is a very common strategy, particularly (but not exclusively) when the system is multi-zoned with some smaller zones to serve. Sometimes it's just the easiest/best way to get there.

Running a mod-con at a fixed but condensing temp means you're not really getting much out of outdoor reset, but generally speaking ODR doesn't buy you a whole lot with fin-tube when it can deliver design day heat at temps <140F- it'll run between 88-92%, most of the time. With some types of radiant floors it can buy a bit more, with slabs it can put the average efficiency above 95% pretty easily.

mage182
02-24-2011, 01:50 PM
My zip is 11731. It's a cape built in 1954 with no dormers (about 1200sqft) with a 600 sqft unfinished basement. The entire downstairs has been renovated with some new Anderson windows and the rest ~10 yr old vinyl windows. The first floor is fully insulated. The second floor is left as is with what I'll assume is inadequate insulation and a freestanding cast iron rad in each room to serve as a temporary solution as we'll be adding a complete second floor with attic in the near future which will add another ~500 sqft. Siding is original aluminum with homasote sheathing.

The first floor (2 bedrooms, bathroom, living room, kitchen) has a total of 40ft of Multipak-80 plus a kickspace heater in the kitchen piped in with monoflow tees. The second floor just has the two cast iron rads. I could probably add another 16 feet of baseboard between the two bedrooms and the living room if necessary. The kitchen already has a 6ft piece on the only open wall available.

jadnashua
02-24-2011, 02:59 PM
Even with adding all of the living space you mentioned, the unit is oversized and won't maximize efficiency. I think a buffer tank may end up your best bet.

tk03
02-24-2011, 07:25 PM
Your heat loss is probably around 50k. I would turn the heating fan speed down by about 50%. If it is too far just turn it up a little at a time. Why let the boiler run up to 105k if there is no need to.

David1
02-25-2011, 09:21 AM
Dana,

Your posts are informative and helpful thanks. I find myself in the same position. My Alpine 150 might be too big but I'm not sure. I am 20 minutes north on 190 so you know the climate. If it is oversized I am thinking it is not by much, maybe I should have 105 ??? The house is 2700 ', half of it 100+years old and the other half 7 years. I have in total 125 ' of fin tube emitters broken into two zones one at 65' and the other at 60'. The plumber installed p/s piping as directed by the installation manual. I believe the plumber did a heat loss calc, he mentioned that he thought I would be using the 105 but the "Load" was right on the edge and he was afraid of 0 degree days.The boiler appears to be short cycling and I question the need of a buffer tank. A side note here, the boiler has been recording Hard Lockout # 25. I have been in touch w/ Burnham, they have some type of fix using a bleed resistor and a wiring modification. Your thoughts ???

tk03
02-25-2011, 05:21 PM
David1
I don't believe he did a heat loss. Did he measure all the door, windows and house size. If all the radiation in your home is no more than 125 ft that is about 75k worth of radiation. Any boiler size larger that that is a waste of boiler. The radiation will not put out more that it is rated for no matter how large the boiler is. Usually the boiler is smaller than the amount of radiation.
Turn down the heating fan speed down to about 3000 rpm's.
Is it making DHW?

David1
02-26-2011, 02:23 AM
TK,

the plan is to install a SuperStor Indirect. The take offs w/ ball valves were installed on the headers.I think he said that the indirect load would be larger than the fin tube. We have a 3 bedroom house 4 people, two teenage age girls ! We do not have the tank yet. At this point I have 50 gallon gas fired hot water tank, 3 years old into a 6 year warranty.

As far as the heat loss, I was not here when he stopped by my wife was. He did mentioned to me later that he was surprised to find that I had 25 windows. I'm hoping he did some type of calc ! On the fan speed, are you talking about dropping the factory setting from 5000 down to 3000?

tk03
02-26-2011, 09:39 AM
Yes down to about 3000 rpm's for the heating fan. If you have a 50 gallon gas fired tank a 35 gallon IWH would give you more hot water. Pipe it in 1" for the best recovery even though the tank has 3/4" tappings for the boiler piping on the tank. Take a look at stone lined tanks as they require a smaller boiler for the same output. That would allow you to tuen the fan speed down for hot water also.

mage182
02-28-2011, 10:14 AM
I ran the boiler for about 6 hours on Satuday (~38*F). The outdoor reset had the unit working on 130* water and when I shut it off the house was at about 62*. Almost the entire time it was on the Max Efficiency level showed.


“Max Efficiency On”- appears when the boiler return temperature is low enough to cause flue gas condensation.

I didn't check to see if the unit was cycling a lot. I was doing other things. But if the return is coming back cold enough to condense then that should be good right?

I found a friend of the family who does HVAC and says he has experience with modcons. He's going to come over this week and look at everything and see if he can tweak it to work the best once the house is warm and it's just maintaining temp.

Here is another question. What is the technical difference between the 80, 105, and 150 models? Gas jets? something to do with the burner element? Would it be possible to pay a technician to swap out those components to lower the model output? I wonder how much the parts would cost?

tk03
02-28-2011, 11:12 AM
The difference is burner size and fan speed.
You can lower your input and get a smaller unit.
When the unit is running press the status button and than there are little arrows on the right and left side mid screen. Press the right arrow until you see black lines. The top two are supply and return temps. Deduct the return from the supply and that is your system delta T. What is the result?

mage182
02-28-2011, 11:48 AM
Using the numbers from above on Saturday. When I was running the unit the water going out was 130 and coming back in was between 117 and 121. So the delta-t is 9-13. Keep in mind this is during the process of heating the house from the boiler being off for weeks, so we started with a house that was approximately 40*.

Dana
03-02-2011, 01:19 PM
mage182: The return water is going to be colder when the house is cold. The more relevent numbers will be be gotten when the house as at or near the conditioned space temp you're planning to run it. But yes, return temps below 120F are good, but short-cyling will still rob the system of efficiency.

I doubt you'll be able to swap burners to "convert" to a smaller unit.

It's hard to estimate the heat load of antique homes with uninsulated air-leaky second floors, but jadnashua is correct- it's still going to be oversized for even a fairly leaky house that size in an L.I. climate (maybe even oversized but ridiculously so for an uninsulated house in the Adirondacks.) And blowing in some cellulose and doing even moderate amounts of air-sealing would usually be a cost-effective comfort & efficiency improvement cutting the heat load (and bills) by a few 10s of percent.

David1: The guy almost certainly didn't do a heat load calc. If he did, he should be able to print out the room-by-room calclulation along with the parameters used, etc. (I'll bet he did one of those "lessee, it's mostly antique, figure 35BTUs a foot, times 2700 come out to 95K, not much margin for the 105, so mebbe we should bump it" kind of calculations. If history is any guide, the 150 would also be considerably oversized for almost any 2700' home in Leominster MA too (even half-antique.)

My 0F heat load (measured) in Worcester is about 30K, and that is in a circa 1923 2x4 stick-built bunglow with known gaps in the insulation, mostly cathedralized ceiling in 6' rafters (not much insulation there, even where insulated), antique double-hungs w/circa 1988 exterior storms for 80% of the glazed area, etc.. It's a bit over 2000' of fully conditioned space and a bit over 1500' of semi-conditioned basement (where it never drops below 65F down there after insulating the basement walls and sealing/insulating the foundation sill & rim joist) so it's pretty much "as good as" conditioned space from a heat loss point of view.

With all zones calling for heat the system is putting out ~42K (measured by delta-T x flow on the boiler loop) due to the hydro-air coil running the main zone when the radiant floors aren't keeping up, but it had no problem keeping up at -8F outdoor temps earlier this season. I literally CAN'T get more than 42K out of the heating system at the water temps & emitters I'm running (!), and that's less than half the full-fire output of the -105. (It modulates higher than that- up to ~60K out under heavy DHW load, but that's a whole other aspect of how I configured the system.) Your conditioned space may be somewhat bigger (maybe not, depending on how big your basement is and how the space is configured, but unless your windows are all leaky single-panes-no-storms your heat load would be well within the bounds of an Alpine-105, and most-likely within the bounds of the -80. (Single-panes with storms have U-value of ~0.5, so figuring 15 square feet per window the glazing factor adds less than 15K to the total at 0F with a 70F interior. Even if contractor-grade double-pane you're looking at less than 10K, lower still if better-quality.)

Your smallest zone is 60' of fin tube, which would deliver only ~15K at minimal condensing temps- about half of your mid-mod output. Your bigger zone is only ~10% bigger so the 150 WILL short-cycle on zone calls if you try to run it at condensing temps. You'll probably have to run it at ~150F or so out, and tweak the flow back to get it to run min-mod with continuous burns between calls from the thermostats, and you'd be running ~87% efficiency. With a buffer tank in series with the boiler so that it particpates in every heating system zone call to stretch out the burns to 10min+ you could run it at low temp and hit the low-mid-90s without cycling the boiler into an early demise.

In general, unless you've taken HUGE measures for reducing the heat load by weatherizing, when in doubt, go lower, not bigger on the boiler sizing. Since this was a replacement boiler, you probably could have done a pretty good whole-house heat load based on last year's gas usage and the approximate efficiency of the old boiler.

With 2 teenage girls taking endless showers you might get better mileage & efficiency out of installing drainwater heat recovery than by installing a SuperStor. Either would give you the capacity you seek:

http://www.ecoinnovation.ca/images/conf%20Equal-flow-R01.jpg

(EFI in Westboro reps the PowerPipe version, and will sell direct out of their WI warehouse (http://www.ecoinnovation.ca/images/conf%20Equal-flow-R01.jpg).) If you have 5' of vertical 4" drain downstream of the shower it can pay off- more than doubling the first-hour rating of a 50 gallon tank by returning half the heat to the incoming water stream. If you later installed a SuperStor when the standalone craps out the efficieny boost would still be there if you feed the SuperStor via the heat exchanger. Bigger is always better on these (longer, bigger diameter), since the installation labor stays the same whether it's a 30% unit or a 60% unit. Payback is shorter for the bigger units if you're running the shower more than 30 minutes/day.

tk03
03-04-2011, 04:52 PM
Again I would reduce the input by turning down the fan speed. That will limit the input even when it needs to ramp up all the way. You can also change the rate of modulation. the boiler has a scale of 1 - 5. It is shipped at 3. Five is the faster modulation rate.

David1
03-06-2011, 09:36 AM
Again I would reduce the input by turning down the fan speed. That will limit the input even when it needs to ramp up all the way. You can also change the rate of modulation. the boiler has a scale of 1 - 5. It is shipped at 3. Five is the faster modulation rate.


I have lowered the fan speed and have seen a marked improvement. My next thoughts are w/ a buffer tank. The loop is piped w/ P/S and the tees are spaced per the installation manual. From what I have seen, it looks like a buffer tank would be installed "inside" that closely spaced tee, in effect replacing it. The supply from the boiler hits the tank directly while the loop supply comes off the other tank outlet. The return from the loop again hits the tank and the return line from the tank (w/ the boiler pump) comes from the tank to the return of the boiler. At least, I think so. Does anyone know where I can find a piping diagram specific to the Burnham Alpine ? I want to make sure I maintain the benefits of the P/S piping. I do not want to void any warranties. Thanks again for all your help !

tk03
03-06-2011, 02:20 PM
Normally the tank takes the place of your closely spaced tees. The system pumps in and out of the tank as does the boiler. I have seen these piped and wired many different ways all of which were proper in their application.
I have also seen applications where it was not installed properly. Most common mistake is an aquastat on the tank to maintain tank temp but affects the ODR temp and maintains temp year around.

David1
03-06-2011, 04:03 PM
TK,

I was not aware that standard buffer tanks need/use an aquastat. I thought that buffer tanks are piped using the four ports and the cavity served as a storage facility. I'm guessing the boiler circ pulls from the tank to maintain flow for the boiler while the zone circs pull from the tank to satisfy the zone stats. I was thinking the aquastat was used when and if the tank functions as an indirect water heater. Am I way off base here ? Thanks.

tk03
03-06-2011, 04:25 PM
Depends on the tanks and application as I stated earlier. I personally would not use an aquastat. Check out boiler buddy. They have a pretty good website for buffer tanks.

mage182
03-07-2011, 07:10 AM
Again I would reduce the input by turning down the fan speed. That will limit the input even when it needs to ramp up all the way. You can also change the rate of modulation. the boiler has a scale of 1 - 5. It is shipped at 3. Five is the faster modulation rate.

I assume this would mean only turning down the fan speed on the heating side and not the DHW side? How would I calculate what to set the new fan speed max to be?

Also if the rate of modulation is shipped at 3. How do I know if I should lower it? And should I lower it to 2 or 1?

Dana
03-07-2011, 09:18 AM
When in doubt, go lower (for highest efficiency and fewest burn cycles), especially when you think/know it's oversized for the application. Start at 1 and only bump it up if it doesn't keep up.

David: There are buffer tanks that operate as "reverse indirects", with aquastat control, but that's not what we're after here. (ErgoMax, TurboMax, Everhot EA all make reverse indirects). Any insulated tank plumbed in series would do.

BoilerBuddy, or ErgoMax buffer tanks are essentially high-mass hydraulic seperators- useful in some system configurations but an expensive way to go for 1-2 zone simple residential systems. In a small primary/secondary system installing an (unpowered) electric tank hot-water heater anywhere in series with the boiler loop an appropriate (and far cheaper) way to add the necessary mass to the system in such a way that it participates in every burn. The electric tank adds only a very modest amount of head to the boiler loop, and won't affect pump sizing.

tk03
03-08-2011, 06:16 PM
Normally I use the higher number for modulation. The faster setting is going to react to turn down faster. The fan speed is as Dana stated start lower and work in the direction you need to.
Remind me what the heat loss and boiler size you have. I can give you a good starting point.

Dana,
Does the electric tank have large enough tappings for the system piping? Aren't they normally 3/4"?

David1
03-09-2011, 03:57 AM
Dana,

I would be interested in looking at a piping diagram for the electric water tank. If a buffer tank sits across the loops, (2) supply outputs and (2) return inputs, how does a standard hot water tank work ? I'm thinking the electric hot water tank has (3) available ports (supply, output and drain). I have watched the "burn cycle" a few times on the boiler at different OATs. It looks like the boiler fires up on average 5-7 minutes. I am thinking that a 10 minute burn would be better, any comments ?

It does appear that the boiler is oversized but I think the min mod output is even with a one zone call. At a quick look, I have about 300 feet of 3/4" copper. At 2 gallons per 100' that suggest I have 6 gallons in the loop and less than one gallon in the boiler. From what I can gather, copper baseboard (existing) is about as low mass as you can get. I'm thinking the hot water slugging back does not help me out very much.

David1
03-09-2011, 04:03 AM
TK,

I plotted my way thur a heat loss calc (3 hours for somebody that does not know what they are doing) and came up w/ 70,000 loss. The boiler that was installed is the Alpine 150. From what I read, it has a min mod ouput of 28-30 K with a max of 120 K. I have two loops split evenly.

Dana
03-09-2011, 08:41 AM
David1: The boiler only has one loop- putting the electric tank in series with either the output or return side (between the zone manifold & boiler) would allow the mass to participate in every burn, independently of how the rest of the system is configured. A short section of 3/4" plumbing on the boiler loop isn't going to present enough head to ANY pump to cause issue with operation of the boiler at the flows you'll be looking at. The 1" taps are only necessary to be able to run it on longer runs at full-fire without running out of margin on the safe delta-T. (see discussion below) The tank is a lot fatter than 3/4"- so you're really only looking at the length of the tank's dip-tube.

300' of fin-tube is capable of delivering ~75KBTU/hr with 120F average water temps, so with your zones are split evenly 150' would still be above min-mod, you should be able to run ~125 or 130F output water without inducing short-cycles, but you may need to reduce the flow (tweaked with a ball valve) to get it to actually RUN at mininum moduation. As long as the return water is ~120F or below you'll be in the 90%+ range. If it doesn't allready have a ball valve in series with each zone, adding ball valves to be able to back off the flow and tweaking each zone to run the boiler at min-mod when it's the only zone calling for heat is much easier & cheaper than adding a buffer tank on the boiler loop- I'd go there first. With that much fin tube in you should be able to achieve continuous burns whenever there's a call for heat (from either or both zones) and stay in condensing mode the entire time.

Combustion efficiency in condensing boilers is all about the return water temp- if you can get it to run 100-110F return-water into the boiler and 120-130F out you'll be in the mid-90s. I'm not sure what the max delta between output and return the Alpine is speced for, but 20-30F deltas are safe for any boiler. At 2gpm a 30F delta between output & return is ~30KBTU/hr, so that's a decent way to guage when you're balanced at or near mid-mod you are when tweaking flows. Even if you have to bump up the output up 140F out with 110F return for consistent heat in every room that's still fully condensing, but 140F out with 120F water on the return would be a few percent lower efficiency.

While 6 minute burns aren't exacting terrible toll on efficiency on a low-mass boiler, reducing the number of burn cycles by a factor of 2 or 3 saves considerable wear & tear, and you can probably get there without adding mass with 150' of fin-tube per zone.

Most heat loss calcs tend to run 25-35%on the high-side of reality- you may actually be closer to 50K. If you have a year's worth of fuel use to work against weather data you can get closer to the true design-condition heat load, but that won't much change how you set up the system. Average water temps still need to be in the 120F range for consistency with fin-tube, and that's more than enough to meet design-day conditions at 120F AWT.

David1
03-09-2011, 08:54 AM
David1: The boiler only has one loop- putting the electric tank in series with either the output or return side (between the zone manifold & boiler) would allow the mass to participate in every burn, independently of how the rest of the system is configured. A short section of 3/4" plumbing on the boiler loop isn't going to present enough head to ANY pump to cause issue with operation of the boiler at the flows you'll be looking at. The 1" taps are only necessary to be able to run it on longer runs at full-fire without running out of margin on the safe delta-T. (see discussion below) The tank is a lot fatter than 3/4"- so you're really only looking at the length of the tank's dip-tube.

300' of fin-tube is capable of delivering ~75KBTU/hr with 120F average water temps, so with your zones are split evenly 150' would still be above min-mod, you should be able to run ~125 or 130F output water without inducing short-cycles, but you may need to reduce the flow (tweaked with a ball valve) to get it to actually RUN at mininum moduation. As long as the return water is ~120F or below you'll be in the 90%+ range. If it doesn't allready have a ball valve in series with each zone, adding ball valves to be able to back off the flow and tweaking each zone to run the boiler at min-mod when it's the only zone calling for heat is much easier & cheaper than adding a buffer tank on the boiler loop- I'd go there first. With that much fin tube in you should be able to achieve continuous burns whenever there's a call for heat (from either or both zones) and stay in condensing mode the entire time.

Combustion efficiency in condensing boilers is all about the return water temp- if you can get it to run 100-110F return-water into the boiler and 120-130F out you'll be in the mid-90s. I'm not sure what the max delta between output and return the Alpine is speced for, but 20-30F deltas are safe for any boiler. At 2gpm a 30F delta between output & return is ~30KBTU/hr, so that's a decent way to guage when you're balanced at or near mid-mod you are when tweaking flows. Even if you have to bump up the output up 140F out with 110F return for consistent heat in every room that's still fully condensing, but 140F out with 120F water on the return would be a few percent lower efficiency.

While 6 minute burns aren't exacting terrible toll on efficiency on a low-mass boiler, reducing the number of burn cycles by a factor of 2 or 3 saves considerable wear & tear, and you can probably get there without adding mass with 150' of fin-tube per zone.

Most heat loss calcs tend to run 25-35%on the high-side of reality- you may actually be closer to 50K. If you have a year's worth of fuel use to work against weather data you can get closer to the true design-condition heat load, but that won't much change how you set up the system. Average water temps still need to be in the 120F range for consistency with fin-tube, and that's more than enough to meet design-day conditions at 120F AWT.


Dana,

I may have mis spoke .......

the 300' is the total run of copper on both zones. The emitters for each zone, (zone 1 = 60', zone 2 = 65') total 125 '. Is that what you understand ?

Dana
03-09-2011, 11:33 AM
Ah- I mis-read that to mean 300' of baseboard.

To get ~28-30K out of it in 60' your talking ~450-500BTU/foot, which would usually require average water temps ~160F. The same 60' of baseboard should still be able to deliver ~10-12K at 120F water temps though, and if your heat load calc is correct that'll be close to the heat load for that zone roughly half the time, so you should still get a significant seasonal condensing benefit.

The cycling solution is to add thermal mass (buffer tank), then tweak the outdoor reset curves to where it's putting out ~150-160F water @ 0F outside. Then bump the curve temps down a bit if it's satisfies the thermostat in less than 30 minutes when it's 15-20F out. The burner shouldn't be cycling at all during thermostat calls at 25F or below if your heat loss calc & curve is correct. It might at warmer temps when the whole house load is below the min-modulated fire, but with even 10-15gallons of additional water to work with the burns should exceed 10minutes even when it's 50F out (very light loads.)

David1
03-09-2011, 01:09 PM
Ah- I mis-read that to mean 300' of baseboard.

To get ~28-30K out of it in 60' your talking ~450-500BTU/foot, which would usually require average water temps ~160F. The same 60' of baseboard should still be able to deliver ~10-12K at 120F water temps though, and if your heat load calc is correct that'll be close to the heat load for that zone roughly half the time, so you should still get a significant seasonal condensing benefit.

The cycling solution is to add thermal mass (buffer tank), then tweak the outdoor reset curves to where it's putting out ~150-160F water @ 0F outside. Then bump the curve temps down a bit if it's satisfies the thermostat in less than 30 minutes when it's 15-20F out. The burner shouldn't be cycling at all during thermostat calls at 25F or below if your heat loss calc & curve is correct. It might at warmer temps when the whole house load is below the min-modulated fire, but with even 10-15gallons of additional water to work with the burns should exceed 10minutes even when it's 50F out (very light loads.)

Dana,

When the P/S piping was installed we took into consideration adding an indirect heater in the future. The take-offs are there w/ ball valves ( I pulled the handles off). If I am adding 15 gallon electric tank (unpowered), should it be installed just after the two return legs from the zones and before the return leg from the future indirect ? I'm thinking I do not want the indirect plowing through the (buffer tank). If I understand this correctly, only zone 1 and/or zone 2 will "use" the added thermal mass. When the indirect is added and the Priority is wired, the zones will shut down on a call for DHW. The indirect will fire up and bypass the buffer tank. Do I have it right ?

If so, does it matter how the tank is piped, inlet vs outlet ? I do not want to install it backwards. My guess is that it does not, just asking? I'm thinking the drain remains and the pressure relief is installed. Thanks again for your input !

tk03
03-09-2011, 07:08 PM
Your fan speed for the Alpine 150 with a 70k heat loss should be turned down from 5500 to a starting point of 2800 rpm's and fine tune down from there.

David1
03-10-2011, 02:26 AM
TK,

The fan speed was reset to 2800 about two weeks ago. I have seen a marked improvement on the cycling. I have not adjusted the mod rate yet, still thinking about that. The min fan speed is set to 1300 (factory), when the gas valve modulates down it drops to 46% (min mod). I was wondering what I cabn do to increase the burn time to 10+ minutes. It makes sense that a 15 gallon tank adds the mass the mod con is missing. Reading back on my past posting, it probably does not matter if the indirect uses the added mass. Just thinking about the piping considerations. As long as the 15 gallon tank is installed on the return manifold and before the "closely spaced tee", I should be fine ? Right ?

tk03
03-10-2011, 08:30 PM
I would drop the fan speed another 500 rpm's and see what that does for you.
Let's review again what the ODR info is including the minimum water temperature.

David1
03-11-2011, 01:53 AM
Lo Outdoor Temp 0 degrees
Hi Outdoor Temp 70 degrees
Lo Boiler Temp 110 degrees
Min Boiler Temp 150 degrees
Boost Time 1200 secs
Max Outdoor Temp 180 degrees

Dana
03-11-2011, 09:00 AM
If you put a buffer tank on the boiler loop of the P/S system it'll contribute some standby loss when operating in water-heating-only mode. It's best to put it in series with either the supply or return manifold of the heating loops only. But in this climate the heating season is 8-9 months long, so the small efficiency hit on water-heating-only would only relevant in the summer. If it would shorten the plumbing to both the indirect & buffer by having the buffer in the boiler loop it's at worst a wash- the standby losses from the less-insulated plumbing can easily exceed standby losses through the walls of an insulated electric HW heater used as a buffer.

The "ideal" spot for the buffer would be to have the closely spaced Tees for the zone supplies right at the boiler-output connection to the tank, and the zone return tees connected close to the boiler return, essentially making the tank the point of hydraulic seperation, something close to this:

http://www.radiantandhydronics.com/RH/Home/Images/0509rh-GF-Fix-lg.jpg

(You may find this a useful read: http://www.radiantandhydronics.com/Articles/Glitch_and_Fix/BNP_GUID_9-5-2006_A_10000000000000597932 and this http://www.radiantandhydronics.com/Articles/Glitch_and_Fix/BNP_GUID_9-5-2006_A_10000000000000201092) (http://www.radiantandhydronics.com/Articles/Glitch_and_Fix/BNP_GUID_9-5-2006_A_10000000000000201092)

But if it's just in series with the boiler output (or return) and the manifold to the zones the it'll still stop the short-cycling.

With fin-tube 110F would usually be too low an output for consistent results at low heat loads, but see how it does. It might be OK until dust-kittens build up in the convectors. Boiler output of 180F @ 0F is probably more than necessary for the actual (as opposed to calculated) loads with 125' of fin tube, but about right if your load is truly 70-75K as opposed to the built-25% margin of many calculations. If the 0F heat load it's actually closer to 55K (likely) you'd be able to keep up with a curve that crosses 160F or 165F @ 0F outdoor temp, and have more condensing time. Even when operating above condensing temps, you reap ~2-3% fuel savings for every 10F you can peel off the water temp. With a condensing burner those savings are something like 8% when dropping from 140F down to 130F though, and you get another hefty chunk dropping the output down to 120F, so setting the curve as low as it can be and still keep up at design conditions counts. Using the boiler to measure the heat load is far more accurate than any Manual-J or IBR type calculation.

Tom Sawyer
03-11-2011, 01:53 PM
All of the delta T problems can be solved with a VFD circulator, say a Wilo

mage182
03-14-2011, 08:42 AM
Those Wilo units look pretty cool. I have an HVAC guy coming over this week to tweak my system. I'd rather lay out the cash for these than try to put in a buffer tank. There really isn't room on the return side for me to pipe anything like that. If the VFDs will fix the deltaT/condensing problems, hopefully they will be a direct swap for the Tacos I installed.

David1
03-14-2011, 12:37 PM
Those Wilo units look pretty cool. I have an HVAC guy coming over this week to tweak my system. I'd rather lay out the cash for these than try to put in a buffer tank. There really isn't room on the return side for me to pipe anything like that. If the VFDs will fix the deltaT/condensing problems, hopefully they will be a direct swap for the Tacos I installed.


Mage182,

Please keep us posted on your freq pumps, it will be interesting to see how you make out. Thanks,

Dana
03-14-2011, 03:08 PM
Those Wilo units look pretty cool. I have an HVAC guy coming over this week to tweak my system. I'd rather lay out the cash for these than try to put in a buffer tank. There really isn't room on the return side for me to pipe anything like that. If the VFDs will fix the deltaT/condensing problems, hopefully they will be a direct swap for the Tacos I installed.

No pump is going to add thermal mass to your system, but ECM drive pumps with programmable features can make it easier to tweak things toward min-modulation. Still...

"In most buildings, according to hydronic heating expert Henry Gifford, the level of savings we will achieve with the high-tech (expensive) variable-speed pump can be more cheaply achieved simply by right-sizing a constant-speed circulator. The reality, however, is that most heating contractors don't do actual calculations for pumps (most probably don't even know how to do those calculations), preferring to cover themselves by significantly oversizing the pumps. For this reason, this new generation of advanced smart pump makes a lot of sense."

http://www.buildinggreen.com/live/index.cfm/2010/8/12/Grundfos-and-Wilo-VariableSpeed-ECM-Circulator-Pumps-for-Hydronic-Heating (http://www.buildinggreen.com/live/index.cfm/2010/8/12/Grundfos-and-Wilo-VariableSpeed-ECM-Circulator-Pumps-for-Hydronic-Heating)

A ball valve approach achieves a similar end by addding head to the loop, lowering the flow rate. Variable rate ECM pumps will save a on electricity over a ball-valve approach, and may be cost-effective in constant flow applications, but not necessarily with an oversized boiler's intermittent cycling, since the duty cycle is already low. The goal here is to stop the short cycling while running it in condensing mode as much as possible. $300 smart-pumps will only get you part of the way there- it won't solve the more fundament design issue which is the imbalance between radation & boiler output that occurs at temps below the crossover where the radation output is equal to min-output of the boiler. It can't help the boiler make longer burns when operating in outdoor reset mode when the boiler output temp is below that critical crossover point, but a buffer tank will. It'll do the right thing during intermittent zone calls on the boiler loop of a primary/secondary though, as long as the radiation can deliver the boiler output at the temps delivered. The real problem remains: we're over-boilered/under-radiated for low temp operation and for the size of the load. If there's too low a delta-T at low temp operation isn't likely from being over-pumped as much as from being under-radiated. It might be the right thing to do if pumping direct (not primary/secondary) using zone valves and 1 pump rather than the 3-pump P/S system David1 has set up. (You'd have to pay close attention to the min-flow rates specs on the boiler to be sure- this isn't a no-brainer to design, but it's not rocket science either.)

jadnashua
03-14-2011, 03:23 PM
How about adding a loop or two to keep the snow/ice off the sidewalk/driveway? If you consider the cost of a snow blower and the aggravation of slipping and sliding around, it may be a useful addition.

tk03
03-14-2011, 08:27 PM
The Alpine requires p/s piping. The idea of most mod/cons is to keep the flow rate up when the boiler modulates back. If the flow in the boiler slows it will kinda defeat the purpose. When modulating keep the flow rate up and reduce the delta-T which extends the run times.
Variable speed pumps on the system will help widen the delta-T so cooler water comes back to the boiler. But you will still heat it too fast. When boilers are over sized the boiler flow rate is more then the system flow rate, so you will have hot supply water reverse flowing between the tees and preheating the water returning back to the boiler.
Over sized boilers are definitely over sized boilers. As stated earlier the ratio of input to water volume/connected load causes the short cycling.
I hate to sound like a broken record but keep turning it down and change the modulation rate to #5 or add a buffer tank.

Dana
03-15-2011, 09:00 AM
Broken records are good, when they're on the right track. (Thanks for the clarification of why all Alpines need to be set up P/S. I've seen several Contenders and Solo designs set up to pump direct thought, but they were DESIGNED, and not oversized for the radiation.)

Reducing the modulation to the minimum it would still take 165-170F water to not cycle on a single 60-65foot fin-tube zone like David1s to run with the radiation perfectly balanced to the boiler output. At 140F output (the beginning of condensing) a single zone can only deliver ~2/3 of the min-mod output. Whether there's enough hysteresis in the boiler's controls to make those cycles sufficiently long is still an open question-more mass may still be the ultimate answer. Alternatively , baseboard is cheap, and if there is sufficient wall length in each room to install enough additional radiation/baseboard that it can deliver design-condition heat at ~140F boiler output you should be able to tweak it to always run in condensing mode, without cycling issues.

mage182
03-16-2011, 12:07 PM
Another thought. Would consolidating the 3 zones I have into 2 make things better? I have the two bedrooms on the first floor on one zone, The living room, kitchen, bathroom on another, and the upstairs on a third. Would combining the two zones on the first floor into one help to deliver more heat? It's all piped with pex in the basement so making a few cuts to combine the two zones isn't a big deal. The only loss there is the money for one circ pump that won't be used.

jadnashua
03-16-2011, 03:29 PM
Probably won't make much of any difference...odds are that those two zones have some current overlap, and forcing them to both come on at the same time (you could do this by controlling both circulators from the same control without cutting or repiping anything) wouldn't make much of any change in the heat load. And, you'd lose the flexibility of separate temps in the individual zones. If you can't demodulate the burner low enough, your best bet is a buffer or increase the total load.

mage182
06-06-2011, 06:01 AM
I'm back to this topic after taking care of some other things. I'm looking into buffer tanks and getting one installed before the heating season in the fall starts.

Based on the article above I have the following questions

Article:
http://www.radiantandhydronics.com/Articles/Glitch_and_Fix/BNP_GUID_9-5-2006_A_10000000000000201092

On my boiler, P1, P2, and the ODR are controlled by the boiler. The zones are controlled by the Taco box. How does the boiler know to turn on P3 and not P2, vice verse, or both when a zone calls for heat? Currently I only have P2 for heating, so that turns on whenever there is a call for heat. With the buffer tank, something will have to make a decision on what combination of P2 and P3 needs to be turned on. The schematic is excellent, it's the wiring/control side of it that I'm trying to understand.

BadgerBoilerMN
06-07-2011, 02:21 PM
I like it better when you talk about insulation :).

There is not enough information here to respond decisively, it is why they make field technicians.

Over sizing any boiler (either for the total design load or for the available insulation) will assure bad performance, raising operating and maintenance costs while lowering potential comfort.

When you oversize a boiler (on purpose or from shear ignorance) it must cycle more often with less efficiency (think city vs. highway miles). When you oversize a condensing boiler that modulates input, "Over sizing isn't usually as big an issue with mod-cons" you may not only suffer short cycling as a result of not being able to transfer the heat through available radiation, but the boiler may also bump off the bottom. Since it is oversized for the maximum load it is often oversized for the smallest load as well.

If may be that the boiler is over-fired. I wonder if the output has been checked.

While your at it a combustion analysis would be in order as it is the only way to determine if you have the boiler "tweaked" correctly. Burnham calls in "fine-tuning".

When you heat domestic hot water, using a ModCon and indirect-fired water heater, the load changes with the potable water temperature and the boiler should modulate downward as the boiler and WH temperature rise. If the controls are not set up correctly, this may not happen. If the boiler is oversized, this may not happen. If the indirect pump is undersized, this may not happen. If the pipe between boiler and indirect water heater is undersized...well you get the picture.

As to DHW priority; it is standard and will not affect the heating mode or even be perceptible unless setup incorrectly. The maximum DHW run time is adjustable on most ModCon boilers.

It is possible to de-rate some ModCon boilers - including the new SAGE controlled Alpine - but the minimum output will stay the same. Ideally a heating boiler should be size to operate between the smallest and largest load conditions, which in turn depend on construction, location and zone loads.

The best time to find a competent hydronic contractor is before you start. It is accomplished by calling the local contractors and interviewing them specifically on the subject of high efficiency (condensing) boilers and more specifically on the computer program they use to determine the output of the boiler you require.

The experienced designer has data for all of North America is able to read and follow the manufacturer's recommendations. The local installer however, must consider his local support. When I specify a boiler, I first look to the local support system for the boiler I want to use.

The specification, installation and maintenance of ModCon boilers is not a DIY project.

mage182
06-08-2011, 05:51 AM
After firing the first two contractors I hired to install my ModCon (the first because he started and then wanted me to wait weeks for him to come finish the job, the second because I didn't like the quality of work he did or his attention to detail), I finished it myself. I know the unit it oversized because I plan on building a large extension in the next few years adding two more heating zones and another bathroom.

My further efforts to locate another contractor that has specific knowledge on how to tune and tweak a Burnham Alpine so that I know it is running at optimal efficiency and provide guidance on whether or not I need a buffer tank to achieve this in the interim have come up empty.

So I have come here to query information from whoever may have some words of wisdom. Your comments on when to find a contractor, design, and implementation methods are all valid, but this isn't the case. I have an installed and fully functioning boiler that I suspect is oversized and a buffer tank has so far been the best route to remedy that. However, All I have so far is the diagram posted above. So I need to know how to properly size the tank, and how to wire it correctly as the article posted above doesn't cover that aspect. Any information needed I would be happy to provide.

BadgerBoilerMN
06-08-2011, 11:18 AM
From the information provided, the buffer tank would have a marginal affect. I would live with your 6 minute cycles (not short for a ModCon) and hurry with the rest of the system, remembering that the more radiation you have the more your boiler will condense. Naturally the radiation has to be balanced to the room and the load. Small rooms with large loads e.g. sun room, present special challenges that may be resolved by the use of a buffer tank, but can usually be addressed by much less expensive control strategies.

A good designer can head off many of the headaches you are suffering.

Every good hydronic system starts with a proper heat load analysis performed by an experienced designer on dedicated software.

tk03
06-09-2011, 12:00 PM
It would help if we could see pictures of the installation. Is that possible?

mage182
06-10-2011, 06:25 AM
Here is what the second plumber that I fired left:
http://share.shutterfly.com/action/welcome?sid=0AbMW7Nk0cs2b3o

Here is as it stands today:
http://share.shutterfly.com/action/welcome?sid=0AbMW7Nk0cs2b7Y

tk03
06-10-2011, 06:13 PM
A few issues I see right away is the IWH tank is not properly piped. It should be 1" (if it is not now) and treated as another zone, not off the boiler piping. The Alpine 150 requires a flow of 11 gpm and the indirect requires 6 gpm. Is that pump for the Alliance a Taco 007? If so not big enough. It is hard to see the boiler secondary piping where it ties into the primary pipe. I am also concerned the ells on each side of the closely spaced tees are too close. You need a minimum of 8 pipe diameters before the tees and a minimum of 4 pipe diameters after. This all affects flow. The distance between the tees not to exceed 4 times the diameter of the primary pipe (not boiler secondary pipe).There should never be nothing between the tees.

mage182
06-11-2011, 12:03 PM
I didn't pipe any of the things you mentioned as you can see by comparing the pics. I just redid what did not technically worked or looked terrible.

This is directly out of the Burnham installation manual,

http://i216.photobucket.com/albums/cc232/mage182/3%20Arcy%20Drive/AlpinePipingDirections.jpg

Showing the tank piped as mine is. The connections on the tank are only 3/4" if that makes a difference. The length of the pipe between the closely spaced Ts is 4 inches so that is correct.

The rest of it is not something that would easily be changed. It would require basically repiping the entire thing which I have no interest in doing. And paying another plumber (which I don't have) at least $1000 to redo isn't in the budget.

tk03
06-11-2011, 04:39 PM
As I stated it was hard to see the area of the piping where the boiler tied in.
You are right the drawing is right out of the Burnham manual. But as you read the manual somewhere around page 39 dependent on date of the manual, it shows a table 12B. 12B states that an Alpine 150 should use drawing 32C or 32D for piping. The not recommended means not recommended piped to the boiler piping.
As far as the piping to the indirect it should be piped in 1" to get the proper flow through the indirect for proper heat transfer from the boiler and also into the tank. Increase the piping to 1" right at the tank. The pump should probably be a Taco 0010 also.
This would help resolve short cycling during production of hot water.

BadgerBoilerMN
06-12-2011, 01:05 PM
Performance may be enhanced by an upgrade to 1" but that is not a guarantee. Given the short distance and the maximum delta T of 35, the manual will allow the use of a UPS1558 or a 007 Taco (which you appear to have). Flow is determined by the size AND developed length.

It appears also that you hired a good mechanic that didn't quite understand why but only how.

The first drawing appears to be correct. It also appears that you have re-piped from the accepted primary/secondary to the direct pumps method, which is accepted by Burnham but not recommended because of the requirement for careful flow considerations...read experienced professionals only.

If I had to guess, the pump on the primary pipe is bigger than the pump on the indirect. If that is the case, I would re-pipe to the original correct pipe schematic and switch the pumps (making sure the axis of the pump I level).

The copper pan is a nice touch but will not stand up to acidic condensate.

Careful of the DIY crowd, another "professional" is always your best bet.

tk03
06-12-2011, 08:13 PM
Your looking at a minimum of 14 ft head. How is a Taco 007 a good choice for this application? I believe it is primary/secondary but again it is hard to see from the picture.

BadgerBoilerMN
06-13-2011, 06:42 AM
"How is a Taco 007 a good choice for this application?"

I write, read and understand, condensing boiler installation manuals for a living. I believe this boiler has been repiped without the bypass.

Over the past 25 years I have found qualified installers in 23 States and 7 Provinces, DIY on a ModCon is the road to misery.

mage182
06-13-2011, 06:45 AM
I'm just going to post up the above references items from the manual for future reference.

P.39 content:

http://i216.photobucket.com/albums/cc232/mage182/3%20Arcy%20Drive/39.jpg

Table 12B:

http://i216.photobucket.com/albums/cc232/mage182/3%20Arcy%20Drive/12B.jpg


As far as the piping to the indirect it should be piped in 1" to get the proper flow through the indirect for proper heat transfer from the boiler and also into the tank. Increase the piping to 1" right at the tank.

The feed side for the tank is 3/4" with a Taco 007. The return side is 1" (I'll assume because that was what was available at my house when the plumber did the install). Changing the feed side to 1" is not more than 30 mins worth of work and an easy fix. But since you're correct (as confirmed in 12B) that the tank should be piped as a zone, should I really bother buying a Taco 010 to replace the brand new 007 that I already have? Or is it feasible to just replace the feed like with 1" and leave the pump and just move the tank over to the extra spot on the manifold when I build the addition?


The first drawing appears to be correct. It also appears that you have re-piped from the accepted primary/secondary to the direct pumps method, which is accepted by Burnham but not recommended because of the requirement for careful flow considerations..

The system is still P/S. All I did was move the feed side which was hanging 3' from the wall supported by almost nothing (including the pumps whose flange valves couldn't be closed because they hit the ceiling joists) over to the wall where it could be supported. I didn't touch the primary loop other than to fix the primary loop circ flange which was leaking.


If I had to guess, the pump on the primary pipe is bigger than the pump on the indirect. If that is the case, I would re-pipe to the original correct pipe schematic and switch the pumps (making sure the axis of the pump I level).

The primary pump is larger (I'll look up the model number tonight).


The copper pan is a nice touch but will not stand up to acidic condensate.

Isn't that what the neutralizer is for? Or does that not neutralize as well as I've read? Most people I've talked to say not much condensate comes out anyway. If I see it starting to corrode I can fabricate the same item out of PVC. That was a fun project.


Are we in in agreement that the system will function without breaking for a while until I start the addition at which time I can move the tank to the manifold and just cap off the connections on the primary loop when I have the new bathroom plumbed and the upstairs heating zone expanded?

Thanks.

jadnashua
06-13-2011, 07:13 AM
The amount of condensate depends entirely on the size of the boiler AND how much it is in condensing mode. If running condensing mode primarily, it can produce a lot of condensate! If, on the other hand, it is running full blast and not condensing, most of the moisture will be exhausted as a vapor. Some of this depends on the length of the vent pipes and where they run. SO, short answer, if you don't have a lot of condensate, your system is probably oversized...

Dana
06-13-2011, 11:19 AM
It can still be grossly oversized, short cycling like crazy, and still return a lot of condensate if operating in the condensing region. It's the temperature of the return water, not the output rate (or output temp) of the burner that determines the amount of condensate. The more radiation you have, the lower the temp that still delivers the heat, and THAT will also increase the condensate volume (which is a good thing, efficiency-wise.)

BadgerBoilerMN
06-14-2011, 05:36 AM
switch the pumps and pray,

for others following this thread, you can find a qualified professional

http://www.badgerboilerservice.com/contractor.html

Dana
06-14-2011, 07:43 AM
Has prayer proven successful in debugging hydronic systems? Any particular mantras, bhodisattvas, or saints work better than others? ;-)

I like the "find a competent pro" approach much better. But I also like to measure stuff before/after as a sanity check, independent of the designer. To be sure "design by web-forum" only works in the simplest of systems, and when loads can be well-estimated by empirical data rather than heat loss calculation apriori.

tk03
06-14-2011, 06:22 PM
I am not sure I understand the moving the pumps or maybe I misunderstand what you are saying. The manual calls for a 0014 or a 26-99 on the boiler secondary pipe pumping into the boiler. The 007 could be used on the tank if the piping was change to a zone useing diagram 32C or 32D.

Dana, isn't it both the supply and return water temp that determines the amount of condensation. You can have part of the boiler at a condensing temp and part of the boiler hotter than condensing temp. That would mean that only part of the boiler is condensing. This might happen when the return temp is getting closer to the high side of dew point where it is not going to condense.

mage182
06-15-2011, 05:51 AM
The pump on the primary loop is in fact a Taco 0014. My two goals now are to switch the piping for the tank to use the extra zone I set up on the manifold before I move in, and to find a competent service professional using BadgerBoilerMN's recommendations to come and do the initial software configuration. Hopefully that same person would be available should I ever need service for the unit.

tk03
06-17-2011, 07:00 PM
The 0014 is actually on the secondary boiler piping. The close spaced tee's are always on the primary and the branches are secondary.

Dana
06-20-2011, 03:15 PM
I am not sure I understand the moving the pumps or maybe I misunderstand what you are saying. The manual calls for a 0014 or a 26-99 on the boiler secondary pipe pumping into the boiler. The 007 could be used on the tank if the piping was change to a zone useing diagram 32C or 32D.

Dana, isn't it both the supply and return water temp that determines the amount of condensation. You can have part of the boiler at a condensing temp and part of the boiler hotter than condensing temp. That would mean that only part of the boiler is condensing. This might happen when the return temp is getting closer to the high side of dew point where it is not going to condense.

Boilers have counterflow heat exchangers- the output end of the HX is at the highest temp end of the gas flow, closest to the flame front. The hottest part of gas flame is on the order of 3000C and the bleeding edge section of the HX closest to the flame front is literally never condensing during a burn, independently of the flame size, even with 120F output water, since most of the gases are still well over the dew point of the exhuaust. But the MAJORITY of the fire-side to water-side of the heat exchange is happening in this section, since it has the highest delta-T from fire to water-side. Whether the output temp is 120F (50C)or whether it's 180F (~80C) the delta-T with the very hot gases of the exhaust isn't much different in percentage terms.

But most of the surface area of the HX is cooler, where the gases of the fire side are already literally thousands of degrees cooler than where they entered the HX, but the delta-T across the HX to the water side is now much lower, and that temperature is governed most-predominantly by the return water temp. To the extent that the return water to output water delta-T is bounded, the amount of HX surface area that is below the dew point of the exhaust gases rises and falls with output temp, but the amount of condensation derived is still governed by primarily the return water temp. The size of the flame, and the output temp are only second-order effects.

Below some firing level there isn't sufficient turbulence on the fire-side for good heat exchange in the low fire/water delta-T sections. Laminar flows create an insulating boundary layer that limits the amount of fire-side gas contacting the HX thus reducing the condensation. This is the technical reason why it's difficult to build a condensing boiler with more than about a 4:1 turndown ratio. At any given return water temp in the condensing zone the sweet-spot is usually somewhere in the lower 1/3 of the flame modulation, but not necessarily at the lowest. Cranking the flame lower than min-mod on most of them they run into laminar flow issues and efficiency falls off very rapidly with fire size as more of the gas volume then escapes without coming into direct contact with the cool end of the HX.

An oversized boiler would be more likely to short cycle, but would deliver the heat at a lower flame modulation, with ever so slightly higher condensation for the same volume of exhuast gas BTUs. At any given return water temp it would still deliver about as much condensation as an appropriately sized boiler, but would be giving up more in fixed losses with every flue-purge & ignition cycles, delivering somewhat lower overall efficiency.

BadgerBoilerMN
10-23-2011, 09:38 AM
Ridiculously oversized...well, depending on the boiler, the minimum fire may well be 50% or more of the design load of the house - or radiation. If this the case and we are just making up numbers here since no proper manual 'J' heat loss was performed - the the boiler could certainly be "bumping off the bottom" while trying to heat a small zone. The boiler could be cycling while make DHW due to several reasons including lack of flow. This is all a bit complicated for the novice boiler installer and certainly not a DIY project no matter how many "plumbers" you go through.

I advise my clients to find the local contractor that is factory certified for the condensing boiler you wish to buy. Short of this find local supplier or rep for any high efficiency boiler they intend to buy and make sure that you will have professional experienced support before the boiler is delivered. If you insist on buying a high efficiency boiler on the Internet make sure you will get the support you need from the people you gave your credit card number to.

Taking advice from folks - however well intended - who have never installed a condensing boiler is a little risky.

mage182
01-04-2012, 02:18 PM
Update

Hey. I just wanted to give an update since I've made some changes, moved into my house, and am in the process of making observations.

I finally found an HVAC guy that works with Modcons. He came over, helped me set up the boiler, and agreed that the tank should be piped as if it were a zone in 1". He said to try that before replacing the pump for the tank because it may not be necessary. I agreed to do that, track the number of cycles per day, the temp at the same time each day, and time some fire times for heating and IHW cycles.

He set the max fan speed for heating to ~2500 (down from the max of 5500) due to oversizing and the max speed for the IHW to ~4000.

A few weeks ago I repiped the pump for the tank so it is piped like a heating zone. It is done in 1" and I'm using the same Taco 007 as before.

The HVAC guy asked me to take down numbers for a few weeks and call him back. If he doesn't think everything is working correctly he said he'll come back with a local Burnham rep he knows to look it over again and tweak.

Observations

It hasn't been that cold in NY until this week. I'm seeing heating cycle times around 10-11 mins.

The count of cycles I have observed over the past 2 weeks suggests that the boiler is firing on average three times an hour. I'm not around enough to say if that is evenly distributed.

While observing some cycles I found that sometimes the zone turns off before the boiler even reaches temp. This was on some of the warmer days a few weeks ago. Meaning if the temp is set at 130 by the ODR, the tstat is calling for heat, but then shuts off when the temp only reaches 120 because the zone is satisfied. Is this still considered short cycling?

I am seeing what I would call short cycling on the IHW tank. The set temp for that is 170. But it will make that temp sometimes before the tank is satisified. Then the boiler will shut off as the water continues to circulate. Once the temp drops low enough it comes on again. Some have suggested placing a bigger pump on the IHW tank (Taco 010 or Grundfos equivalent), but will that really improve anything? I don't see how pumping the water through the coil faster will help heat the tank more efficiently?

the office upstairs on it's own zone for now is the only room in the house with an old cast iron rad. That obviously stays warm a lot longer than the fin tube. Is that a better heating method than the fin tube? I have 50 feet of cast iron baseboard sections in my garage that I could swap out with the fin tube over the summer. But would it be worth it?

Dana
01-05-2012, 12:19 PM
It's not considered short cycling unless the boiler's burn time is very short. It's the burn time that counts, since every ignition cycle and flue purge it "throws away" a fixed number of BTUs. If it's burning only 30 seconds and purging for 60 it's an efficiency-disaster. But if it's burning for 10 minutes you're in efficiency-heaven.

The fact that it's not reaching the ODR temp at the output before the t-stat is satisfied is an indication that the reset curve might be too high- you may want to bump it down a notch or two.

Pumping faster through the coil creates more turbulence for better heat transfer, and lowers the delta-T across the coil (and boiler), which may be the issue. The boiler may be turning down or shutting off before the tank is satisfied if the controls are trying to protect the boiler from the stresses of a delta-T greater than the boiler can tolerate. (I don't know if your boiler's controls do that or not.)

Swapping out the fin tube for the cast iron baseboard rusting away in the garage is absolutely the right thing to do. Fin tube has very low thermal mass, and less predictable at low-temp (<125F) output, whereas cast iron baseboard usually has somewhat more water volume thermal mass, and substantially more thermal mass in the form of iron, and has a fairly linear output at low-low temps that will track reset curves better when the heat loads & water temps are quite low. Both factors make it better for use with a mod-con, since the higher mass keeps it from short-cycling at low output, and you can run lower reset curves without running into comfort issues at very low loads where the fin tube craps out, and the cast good keep working. It takes ~75lbs of cast iron to equal the thermal mass of a single gallon of water, but it takes 50' of 3/4" fin tube to equal one gallon. Weigh the cast iron, do the math. What's more, cast iron baseboard has that nice radiated-heat glow when it's cold out, whereas fin-tube's heat transfer is predominantly convection- it heats the air, whereas radiators & cast iron baseboards can heat the humans & pets directly via radiation- it's just plain more comfortable. I'd do it in a heartbeat if it were my house. (I'd even scrounge on Craigslist for lower cost replacement goods if there was a bunch of fin-tube to replace. It's quite expensive new, but it's often $10-20 foot, sometimes less, as private-sale surplus-used. )

mage182
01-05-2012, 01:59 PM
Thanks for the reply.

This question might go in a different direction. But if having burn cycles of at least 10 mins isn't short cycling, then is having the thing run all the time bad? The past few days (It's been cold with highs in the mid 30's, lows in the low teens) I've been seeing 60 cycles a day just for heat. I've noticed they're mostly for the zone with the living room, bathroom, kitchen on it. That would mean every hour the boiler runs 3 x 10 minute burns with 3 x 10 minute off periods. In a house that 's STUFFED with roxul insulation, vapor barrier, all window gaps foamed, shouldn't the heat not have to run as much considering I keep my tstats at 65?

I have no problem with the unit running, I just don't want it to crap out in 5 years due to wear.

As far as the cast iron baseboards go, I didn't use them in the first place because I don't have the compression fittings to attach the sections and I couldn't find end caps for them. I'll put more effort into that this summer.

When I put in the fin tube last year I did a heat loss analysis to determine how many feet I needed for each room. Does that go out the window with the cast iron? Should I just cover all walls that are convenient which is mostly more than the fin tube covers knowing that it will add to the heating mass and keep the room warmer for longer resulting in less cycles for next winter?

jadnashua
01-05-2012, 03:12 PM
Cycles tend to wear things out faster than constant running.

Dana
01-06-2012, 07:18 AM
The 140-200F BTU/foot specs for cast iron baseboard are very similar to run if the mill fin-tube (roughly 600BTU/ft @ 180F & 1-4 gpm flow.) Adding length is fine & good for lower the operating temp & increasing thermal mass mass, but be sure to add it proportionally for the rooms within the zone to ensure the room-to-room balance doesn't get all out of whack. See: http://www.usboiler.net/products/baseboard/baseray/assets/io-manual.pdf and http://www.weil-mclain.com/en/multimedia-library/pdf/weil-mclain-pdf/products/baseboards/snug-baseboard/en-snug-072011.pdf compared to http://www.slantfin.com/images/stories/Technical-Literature/ratings_fineline30_r.pdf The performance of fin-tube at sub-100F is off-the charts variable- dust-kittens & anything that can impede convection hurts it considerably. Cast-iron's heat transfer output at low temp is largely radiated heat, whereas fin tube's output is dead without good convection.

Firing nearly continuously at or near the minimum burn rate is the holy grail of efficiency & boiler-longevity. If your minimum burns are 10 minutes that's GREAT for the boiler's lifespan. What kills a boiler in short years is running 20+ burn cycles per HOUR all season long. At 3 burns per hour when bumping off the bottom you're in excellent shape. Keeping the temperature down to where it's nearly always condensing will do wonderful things for efficiency. Since from empirical observation water temps are not reaching the ODR programmed temps before the t-stats are satisified it's clear that you have room to lower the curves, which should lead to even longer/fewer burns during the colder weather, when the heat load of the house is above the minimum-fire output of the boiler.

mage182
11-15-2012, 07:55 AM
Update

I spent a good amount of time over the summer working through the sandblasting, assembling, and painting of two different brands of cast iron baseboard. I took out all the fin tube (except the 2ft section in the bathroom) and replaced it with the cast iron. I found some paperwork on the output of the cast iron and found it to be less than the Multipak 80 I had so I installed a few more feet not only to match the numbers but for continuity since the cast iron is harder to install.

The boiler has now pretty much ceased to short cycle at all. The heat is much more comfortable and even. When I expand I will make a point of sourcing more cast iron from Craigslist, or buying new if necessary.

My two problem items going forward are:

1. I have no end caps for the cast iron. I was hoping by using all brass fittings on the ends it would look nice enough to leave uncovered, but it doesn't. American Standard and Radiantrim haven't been produced for some time now so finding end caps is near impossible. I've drawn up a few designs I'm going to try with 1/4" oak veneered plywood hopefully using magnets to hold them on.

2. I'm feeling heat in the rads close to the return side of the zones when the IHW zone kicks on. This is on priority so no other zones are running when making hot water. I'll start by saying there are no flow checks on the zones, only one on the zone for the IHW. What I'm thinking is happening is as the tank calls for hot water, the water is being pumped into that zone and drawing water back out of the other zones as the water flows through the manifold. This water is then being replaced at the other end of the zone as the water flows back from the tank into the return manifold and is also flowing into the zones on the return side. This is probably hurting my delta t numbers when the heating zones first come on as well as causing some unwanted heat.

Are installing flow checks on the 'push' side right after the pumps enough? or do I also need them on the return side?

I want to use swing checks, but from what I've read those have to be installed horizontally which would be a problem for me. If I need to install vertical would I need to use spring loaded checks? Those look like they hinder flow a lot and I've read comments about them chattering.

Any input?

Dana
11-15-2012, 11:11 AM
It's amazing what a bit of real-radiation and some thermal mass can do for comfort compared to fin-tube, eh?

I'll let the pros comment on different types & orientations of check valves- there's not a lot of rocket science to it though. A worst case solution is to inserrt zone valves, which reliably block flow in any direction when the zone is off no matter how interactive/leaky the zone loops are. They reliably block parasitic convection that might otherwise occur with very-low-head check valves.

Now that the boiler isn't short cycling you should take the time to dial in the reset curve and really max out the condensing efficiency.

mage182
11-16-2012, 07:30 AM
Guess I spoke too soon. Woke up this morning to a semi cold house and a hard lockout code 25: Internal control failure. (Reset the control. If problem reoccurs, replace the Sage.)

Blackman (supply house) says to call Burnham. Burnham says to call a local tech. I called the first 10 techs on the Burnham site that they list as affiliates and none of them work with the Alpine models.

The only thing I found is this:

http://www.heatinghelp.com/files/posts/10961/Burnham_Alpine_Bulletin.PDF

Which I can do all of myself, although I doubt Burnham will send me that boot for free and if I want it I'll end up paying for it. I've found them to be very lacking from the customer service standpoint.

BadgerBoilerMN
11-17-2012, 10:02 AM
We are a certified Burnham boiler dealer here in Minneapolis and specialize in the Burnham Alpine and other condensing boilers. The manufacturers are not set up for DIY as it is impractical -read impossible- to directly server thousands of retail customers lacking trade skills and tools. High efficiency condensing boilers are almost always the best fit for new construction or retrofit for natural gas is available but installation and annual maintenance is the key to safe, reliable, efficient space and water heating.

An example is the short-cycling of the indirect water heater (IWH), we find as a common complaint. First in most condensing boiler software there are two settings, one for the potable water temperature in the tank and a second for the "design" water temperature i.e. the set point the boiler will try to maintain while heating DHW indirectly. This temperature is typically factory set to 180-190°F comfortably maintaining a differential temperature to assure efficient heat transfer. If boiler, pump and IWH are properly matched no cycling should occur, rather the boiler will start up to full-fire and gradually modulate downward until the call from the tank is satisfied.

mage182
11-19-2012, 06:43 AM
Burnham won't do anything without a certified rep diagnosing the problem and then ordering whatever parts are necessary. So I sat down with the list on contractors on their site and started calling them and found that either they wouldn't look at an Alpine because they don't work with them, or they're still so swamped with calls from Sandy that they said it would be a while before they could schedule a call. I've been increasing the distance of the contractor from my location, hopefully I'll hear back from the ones I called this morning. The unit is only a year old so at least everything should be covered under warranty once I can get someone to come over.

Badger, out of curiosity, how much would you normally charge for an annual maintenance call for an Alpine? Is it something that is required every year?

Also, I was getting short cycling on the IWH, but after doing some calculations I was able to get it to cycle just once on a call in almost all cases. I adjusted down the max fan RPM. My question is, if the temp sensor on the tank has no communication with the boiler other than to call for heat or not (call it binary 0/1), how does the boiler know at what rate it should modulate downward in order to not short cycle before the call is satisfied? I had initially set up the tank at 180 degrees and set the max fan speed for that call based on the minimum boiler output on the tank spec sheet, but I was getting short cycling. Does that infer that the pump zone pump for the tank has a gpm rating that is too low?

jadnashua
11-19-2012, 09:02 AM
Most IWH sensors I've dealt with (and that's not many?!) are that they are thermistors which means, if they are calibrated to the boiler's control circuit, it knows what the water temp is in the tank. If it's just an aquastat, that would just be a switch. SOme aquastats have two switches in them, a high and a low, and it tries to keep things between the two, but it has no idea how far from the high (which would turn it off) or the low (which would turn it on) is.

mage182
11-26-2012, 02:18 PM
Someone finally came to look at my Alpine. He said the control unit is fried from power surges during Sandy. He said that Burnham won't cover it under warranty and that I should have my homeowner's insurance cover that as well as the rest of the damage to my house. The only problem is that he has already ordered a few replacement control units and they are 6-8 weeks back ordered.

He recommended I talk to my insurance company and see if they'll just pay for a new boiler.

jadnashua
11-26-2012, 04:20 PM
Something like this can help a lot with weird power problems...http://www.amazon.com/ICM491-Single-Phase-Voltage-Monitor-Misc/dp/B000LEVBF8/ref=sr_1_7?ie=UTF8&qid=1353975549&sr=8-7&keywords=icm+voltage+control

mage182
11-27-2012, 06:09 AM
I was thinking more something like this:

http://www.tripplite.com/en/products/model.cfm?txtSeriesID=838&txtModelID=4910

My uncle is an electrician and told me he would install a surge protector for the whole electrical panel that goes in the top slot of each bus on the panel. But that won't help with voltage regulation, only spikes.

I haven't been able to find any economically priced hardwired voltage regulators. Is it acceptable to wire a standard 3 prong plug on to my feed to the boiler and plug it into this before going to the cutoff switch?

jadnashua
11-27-2012, 07:20 AM
My boiler is plugged into a receptacle, so at least where I live, it passed code.

That device monitors the power, that controls a relay that can be used to disable operation if the power is out of range (high or low). Plus, if the power is flakey, it will not energize the relay until it stabilizes, and you can set a delay after it's stable before that happens. Adding whole house surge suppression would take care of the rest of the things. I have one in my HVAC system that disrupts the 24vac control voltages so that nothng can turn on until the power is stable. I rely on the whole house surge suppression to handle the spikes and noise, and this to protect the motors and compressor from severe brownouts.

Depending on the panel, you may be able to plug a surge suppressor in as a CB-like device, or there are numerous panel surge suppression devices available with varying degrees of protection. I put one from Mersen (sp?) at my mother's house after she lost the control board in her frig and the microwave on the same day. There are a few threads discussing this you can read for thoughts - use search.

mage182
12-01-2012, 09:28 PM
I ended up ordering this model

http://m.tripplite.com/en/model.cfm?txtModelID=208

It should be here Monday so I'll wire it up then.

I ended up getting a new control module thurs. I ordered it from a supply website and they happened to get one in stock. I swapped it out and the new one works. I put in all my old parameters. However, the repair module works with all models of the boiler so you have to pick the right one (it comes defaulted to the 80 model). I found that you need a factory password to change this which I don't have. Burnham would not give it to me and the same tech I had come over last time told me it would be at least 2 weeks before he could come over.

Does anyone know the 'factory password'?

Is it bad to run the boiler with the model set to this setting?