Newbie with Alpine issues

[tom3holer]

Hi,

I am new here and this is my first post.
Was up till 2:30 this morning reading all I could and am so impressed at the level of advice and knowledge on this website.

My home, located on Cape Cod Ma, is an old Sea Captains house built in 1860 of around 3000+ sq/ft. It was retrofitted at some point before I bought it 22 years ago with baseboard fin tube raidiators. The downstairs is divided into 3 zones and the upstairs is one zone for a total of 4 zones. 10 years ago we had cellouious blown in insulation done. It was a poor job as I have found many gaps over the years during remodeling.

To the issues. I replaced my 20+ year old W/M VHE gas boiler with a Alpine 150 this last Spring. I also had installed by the same plumber a new superstor 45 gal water heater. All seemed fine till we got into the colder months of the Fall and this Winter. The kitchen in particular on days of 30 and below I could not get above 68-69 deg many mornings. The raidiators seemed sometimes hot, but most of the time luke warm to almost nothing. This all while the tstat was calling for heat. The boiler would fire and come up to temp then shut down. This naturally went through the long startup process thus keeping the average water temp low. The installer which I called over didn't have a clue as to why it was shutting down with one or more zones calling for heat. I read the manual and did spent a good deal of time in the basement watching the boiler run. It didn't take long to realize what was going on.

The default "Central heat diff above" is only 2deg. It was always overshooting and thus shutting down. I upped this to the max of 10deg and that was much better. It didn't short cycle as much. I did read in the suppliment to the owners manual that the new rec setting is 5 deg. I insisted the installer contact the factory rep for our area and ask him to come over and look at the installation. I realized after asking the installer if he had tweeked any of the settings and he replied "Na I just leave them at the factory settings, he didn't have a clue. The factory rep came over with my installer, but didn't seem to offer any suggestions. He lowered thew central heat mod from 5000 to 4900 but that was all.

I would like to tweak this system to get the best effiency I can and have no quams calling an engineer over to elaluate the setup and settings but not sure there is one here on the Cape.

From what I have read I am way over boilered. I have Taco pumps on each zone which most likely flow way to many GPM.
The manual calls for 160-190deg water for the baseboard I have. From what I have read isn't 140 more in the range for best effiency?

Thank you in advance for any suggestions and advice,

Tom

[jadnashua]

Hindsight is what can cause you to kick yourself...yes, it is likely the boiler is oversized. An outside reset control would adjust the boiler setpoint to the need, rather than using a fixed temp. Multiple zones may be making the problems worse with a big boiler since it can't modulate down far enough to accommodate the actual load except maybe on the coldest days. The baseboard heaters have a variable heat output that isn't quite linear, especially as you get approach the lower range, but they still produce heat. The idea of the cooler radiators is to adjust it to your need and to get the return water cool enough to allow the boiler to run in condensing mode, reaching its maximum efficiency.

[tom3holer]

Jim

Thank you for the reply. On the down stairs we have 3 zones. One in the kitchen and the other two for the other rooms. I am considering combining the other rooms into one tstat, so that tstat controls both circulators. Will have to check the data sheet on the Taco SU-504 zone controler and see if it can handle two circulators
.
A couple of things I am having trouble understanding are:

The Alpine manual calls for 160-190deg setting for the fin/tube baseboard the house has. At those temps the Delta T will never be high enough to have the return water get to 120 or so, as as I have read it needs to be, for the condensing part to work.

The previous system had a VHE boiler with a Suporstor 45 or 50 gal indirect water heater. We ran out of hot water quite frequently even in the summer. We do not take long showers either. The new system is using a new Suporstor 45 gal tamk. The installer said you should be able to run the hot water continously and never run out. The DHW priority was wired wrong as I discovered and had him come back and correct it. Still, last evening my wife ran a load of wash then after the washing maching has stopped using hot water she took a shower, half way through the shower she said she had the knob up to full hot and it was bairly hot enough.
The basic problem I see here is similar to what I saw before only somewhat exagerated. The HW is set at 135deg and at some point the HW tstat senses the tank water is getting too coll so it calls for heat. Now the whole prepurge etc. cycle starts and its a while before it fires off further lowering the water temp. By the time its up to speed the cold incomming water had lowered the tank to an unacceptable temp. Is this just an inherant problem with this type of DHW system or is there perhaps a way to change the tstat so it will kick in earlier so as to get a head start?

Thanks again,

Tom

[tom3holer]

Jim

Thank you for the reply. On the down stairs we have 3 zones. One in the kitchen and the other two for the other rooms. I am considering combining the other rooms into one tstat, so that tstat controls both circulators. Will have to check the data sheet on the Taco SU-504 zone controler and see if it can handle two circulators

A couple of things I am having trouble understanding are:

1: The Alpine manual calls for 160-190deg setting for the fin/tube baseboard the house has. At those temps the Delta T will never be high enough to have the return water get to 120 or so, as as I have read it needs to be, for the condensing part to work.

2: The previous system had a VHE boiler with a Suporstor 45 or 50 gal indirect water heater. We ran out of hot water quite frequently even in the summer. We do not take long showers either. The new system is using a new Suporstor 45 gal tamk. The installer said you should be able to run the hot water continously and never run out. The DHW priority was wired wrong as I discovered and had him come back and correct it. Still, last evening my wife ran a load of wash then after the washing maching has stopped using hot water she took a shower, half way through the shower she said she had the knob up to full hot and it was bairly hot enough.
The basic problem I see here is similar to what I saw before only somewhat exagerated. The HW is set at 135deg and at some point the HW tstat senses the tank water is getting too coll so it calls for heat. Now the whole prepurge etc. cycle starts and its a while before it fires off further lowering the water temp. By the time its up to speed the cold incomming water had lowered the tank to an unacceptable temp. Is this just an inherant problem with this type of DHW system or is there perhaps a way to change the tstat so it will kick in earlier so as to get a head start?

Thanks again,

Tom

[tom3holer]

Jim

Thank you for the reply. On the down stairs we have 3 zones. One in the kitchen and the other two for the other rooms. I am considering combining the other rooms into one tstat, so that tstat controls both circulators. Will have to check the data sheet on the Taco SU-504 zone controler and see if it can handle two circulators

A couple of things I am having trouble understanding are:

1: The Alpine manual calls for 160-190deg setting for the fin/tube baseboard the house has. At those temps the Delta T will never be high enough to have the return water get to 120 or so, as as I have read it needs to be, for the condensing part to work.

2: The previous system had a VHE boiler with a Suporstor 45 or 50 gal indirect water heater. We ran out of hot water quite frequently even in the summer. We do not take long showers either. The new system is using a new Suporstor 45 gal tamk. The installer said you should be able to run the hot water continously and never run out. The DHW priority was wired wrong as I discovered and had him come back and correct it. Still, last evening my wife ran a load of wash then after the washing maching has stopped using hot water she took a shower, half way through the shower she said she had the knob up to full hot and it was bairly hot enough.
The basic problem I see here is similar to what I saw before only somewhat exagerated. The HW is set at 135deg and at some point the HW tstat senses the tank water is getting too cold so it calls for heat. Now the whole prepurge etc. cycle starts and its a while before it fires off further lowering the water temp. By the time its up to speed the cold incomming water had lowered the tank to an unacceptable temp. Is this just an inherant problem with this type of DHW system or is there perhaps a way to change the tstat so it will kick in earlier so as to get a head start?

Thanks again,

Tom

[tom3holer]

Sorry for the triple post, My bad.

I am having a bit of trouble with my good old IE and this website......

Tom

[BadgerBoilerMN]

Nothing beats a condensing boiler for space and domestic hot water heating. They are more efficient, create more comfort and domestic hot water, at a lower operating cost per dollar invested than anything on the planet...if the system to which they are attached is properly designed, installed and maintained.

Your problem is with the installer. Call the factory and ask them for the a local certified contractor. The contractor will need to check the piping and pumping arrangement and then set the ODR to fit your climate and your "radiation". Fin-tube can be reset for temperature, but the slope is steep and the range short. If there is in fact no factory trained technician in your area (unlikely) you may call any factory trained Alpine boiler technician offer to pay him to evaluate your system over the phone. This should be done with the aid of some pictures and data then changes made with your "plumber" present. We do this all the time for contractors and homeowners alike. If it is just a programming problem the homeowner may be sufficient. If the system must be re-piped the plumber must be convinced to do what's right.

The DHW is a critical sub-system that must be properly designed, just as the boiler should be sized for the heating load. The indirect water heater specified should certainly keep up with the loads you describe as it is fired at nearly 3 times the rate of a standard gas-fired, low efficiency, tank-type, water heater. There are many ways to control the indirect, depending on the various components used and how the boiler controls interface with it.

Most indirect water heaters should have a mixing valve, tempering the DHW set to 140°F and mixed back down to 120°F or so, thus extending the dump and draw-down capacity.

[tom3holer]

Badgerboilermn,

Thank you for the reply. The first thing I plan doing is to have a good heat loss evaluation done. I keep hearing a recomendation for a "Manual J" heat loss done. If I can find someone that actually can do it locally what can I expect to pay for the evaluation? I know it will be well worth it even thought it should have been done before the installation.
So is it possible to actually get the burner into a condensing mode when running the recomended output temps of 160-180? As mentioned before the factory rep came by with my plumber and changed the mod rpm down 100 and went to reset the over temp limit that was factory set at 2deg but I told him I had already done that and that was all. He did ask my plumber came up with the 150 size and he told him that was what he pulled out. He didn't comment but I think it was out of respect to the plumber with me being there.
You must be busy in Msp. I just retired from Northwest now Delta as a pilot and spent many cold days in the Cities at our training center.

Thanks again, I'll post again when I get the evaluation done and find a factory trained tech.


Tom
Thanks a lot for all the advice guys.

[jadnashua]

Fintube convectors rely on there being a big enough temperature difference to create a draft around it to convect the air through them to heat the room...a flat plate or old clunker works better at simple radiation. But, they will produce heat at a lower temperature, just not as effectively. Most days, you do not need their max output. If you study the spec sheet, they'll give BTU output at various inlet temperatures. They can only generate their maximum heat when you supply them with a narrow range of hot water, but they will continue to work at a lower temp...the spec sheet should describe that.

Most boilers can be set to adjust their outlet temperature based on the zone. On mine, it normally runs at no more than 130-degrees outlet until the IWH calls for heat on its priority zone, then it fires up to 190-degrees or so until the IWH demand has been met. With a small 45-gallon tank and that large boiler, it should be able to keep a shower going for a very long time. Dumping most of it to a tub or washing machine first means it has to start from a much lower temp, though. While I probably could have gotten by with a smaller tank, I have a 60-gallon IWH so I can fill a large 6' air tub. I also wanted to be able to take a long series of showers, as when I have house guests, and one bathroom (small condo), I didn't want to run out. With the boiler I have, and that tank, you could shower pretty much all day and not run out. It does take a few minutes to recover after filling the tub, though.

WHen I did my bath renovation, I put in a thermostatically controlled tub/shower valve...it adjusts itself as the WH tank's outlet temp drops until it's using all hot, if that's what's required, to maintain the user's set temperature.

I'd also bump the IWH setpoint to 140-degrees to raise the amount of energy stored there, but only after installing a tempering valve, if it doesn't already have one.

[tom3holer]

Jim,

Thanks again for the reply. No it does not have a temping valve. The plumber initally set it to 120deg and said that will work fine.
That is on the list to do. Tomorrow I hope to locate a good heating tech to do a heat loss study. Is the Manual J really rthe way to go as I've read?

Tom

[jadnashua]

Unless you're prepared to possibly change the boiler, it would be good info to have, but may not help much. There are ways to make what you have work better, possibly a buffer tank, and possibly combining zones so the load is bigger, but that would somewhat depend on what the manual-J analysis says.

[tom3holer]

I do realize I am probably stuck with the boiler I have but the Manual J would help with deciding how bad it really is.
Now to find someone in my area that knows how to do one.

Tom

[BadgerBoilerMN]

Some "condensing" boiler will feature multi-zone temperature control and all now have DHW priority and will run to a relatively high "fixed" temperature for making DHW. Your fin-tube should be set to a relatively high design temp, but as jad suggests, this is for the coldest few days of the year. In the shoulder months the average water temperature should easily bring the return below 130°F where a boiler will begin to condense and exceed the AFUE number printed on the yellow tag.

More than being essential information, the "Manual 'J' is a good indicator that your heating technician is brighter than average and at least smart enough to have his local distributor produce on for him. No smart contractor will produce a good heat load for free but he should be able to show you a sample of his work. The smart Burnham Alpine contractor will also know that this particular ModCon can be de-rated in the field. This does not cure all the ills of an over-sized condensing boiler, since the minimum output will likely be too high still. But it can help.

[tom3holer]

I called a couple of contractors today and found one I think I will be pleased with. The gal answering the phone knew exactlly that I was talking about when I asked if they could they do a "Manual J" alanysis. She was very surprised whenI told her the plumber that replaced my boiler never did one. She said we would have to charge you and I said absolutely I expect to pay for it. She thought it should run 1- 1/12 hours. She also said their head tech which would do the alalysis was trained by Burnham on the Alpine. So lets see what he comes up with.

Tom

[Dana]

This system is probably an efficiency & operational nightmare- not only is it broken up in to four zones, the boiler is about 3-5x oversized for the space heating load. Typical pre-1980 20th-century construction usually comes in at roughly 15BTU/foot of conditioned space in eastern MA, but it varies by quite a bit- 20BTU/ft is on the high side, and usually rectifiable to something lower in a cost effective manner with air-sealing and insulation measures.

The window/floor ratios of 1860s construction is typically 1/2-2/3 that of typical mid-20th century construction, and even if it has original double-hung single-panes tightened up with storm windows rather than code-max U0.34 double-pand, with some amount of air sealing and retrofit insulation they rarely break very far out of the 15BTU/foot at the ~10F 99% outside design temp. ( Only in rare instances is it not possible to retrofit-weatherize a mid-19th century antique into that range without creating a condensation & rot problem. On early 19th century houses with clapboards nailed directly to the studs, no sheathing it can be a real problem if you insulate. But wide-plank sheathing with paper air-barrier under shingle siding was pretty common on Cape Cod by 1850, and that's usually something that can be insulated safely.) Assuming your contractor managed to insulate at least 2/3 of the wall area, and have some amount of attic insulation, its unlikely you'd be as high as 25BTU/foot, but a careful heat load calc would tell all.

Even at 25BTU/ft that boiler is still 2x oversized for the whole-house load, and probably more than 10x oversized for the smallest zone. If the zone with the shortest total length of baseboard can't deliver a large fraction of the minimum fire output of the boiler at a condensing temp (125F average water temp max), it's going to short cycle. Combining zones or adding radiation is likely going to be in order to tame this beast, even with a field-derating fix.


For yuks, assuming you have storm windows or clear-glass double panes add up all the window area in square feet, as well as the doors, and multiply that by (U0.5 x 60F=) 30 BTU/foot. Then add up all of the wall area (less windows & doors), add that to the attic floor are an multiply it by (U0.1 x 60F=) 6 BTU/foot. Add your windows & doors BTUs to your wall & attic BTUs, that's going to be the very rough heat load of the house, unless it's the draftiest, leakiest house on the Cape (and that can be rectified.). The true heat load at 70F indoors/10F outdoors won't be 2x that, even if with some air leakage and insulation gaps (and no foundation/basement insulation.)