Converting oil to gas. Have 10 year Weil Mclain. Would appreciate advice and costs.

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Dana

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Hi Jim,

Thanks for chiming in. Yes I do understand that the boiler sizing isn't affected by an indirect water heater. We are JUST 4 showers - and 2 of them are for only Amy and I. One of the heating guys who was here claimed we'd need to add 40K for an indirect. It's very nice to know he is either ignorant or intentionally lying.

My question at the end RE: indirect was whether this Use Case would change a recommendation at all via "med eff gas boiler" vs "mod/con". Or if it would perhaps affect the recommendation of any particular make/model boiler selections. I was thinking that some makes/models might be especially good choices if I were to also add an indirect water heater - perhaps they are already set-up for this and I wouldn't need to buy extra valves/pumps. That was my thought process for this question. I can see where my intentions could be easily misconstrued - and thank you for getting me to clarify it.

See my comments regarding boosting showering capacity vs. indirect sizing on your other thread.

Words to live by:

Never ascribe malice to that which could be explained by ignorance or stupidity.

There's a wealth of ignorance about this stuff in the heetin' ''n' plummin' biz. Back in the day it was common to size the boiler for the peak water heating load, to hell with the average operating efficiency, which is how a lot of older homes ended up with boilers 3-5x oversized for the heat load, but we don't need to repeat those mistakes if we know better.
 

jefferson17

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Hi Tom,

Thanks for chiming in! It is so great to have access to you, Dana and the others here and benefit from your knowledge and experience!

>> Never add anything for the indirect load. It is an intermittent load and over-sizing the boiler by say 40K for what amounts to probably less than an hour of run time daily makes no sense and is wasteful.

Understood. And that makes perfect sense. Apparently, the heating guys who have come out here either don't know that - or they were being dishonest w/ me. Which? Take your pick :)

>> Boiler controls like the Taco SR and ZR series relays provide for hot water priority which in essence switches all power to the indirect when it calls. A nice feature and it is switchable, honestly I rarely use the feature.

Perhaps some of the boilers have this type of feature integrated? It's nice to hear that it may not even be all that necessary, even if available. The house won't exactly get cold in the 10-15 min that it takes to recover an indirect.

>> A 40 gallon indirect will give you all the hot water you need.

I hear you. If a 50 gallon isn't much more money I'd probably do that, if only to feel better about having an extra 10 gallons on hand.

>> As far as boilers go a lot depends on what is available in your area. You want equipment that you can easily get parts for should it break down and while I am a fan of Buderus and Lochnivar if you don't have a local supplier you should probably go with what is available.

We are on the NJ border about 25 miles North of Philly and 50-60 miles from NYC. So I would hope that all major brands would have pretty good availability out our way. Buderus, Burnham, Triangle Tube and Peerless are on our short list. Dana seems to like the Burnham ESC series and I do like the notion of having some reliable cast iron. I keep reading and reading about condensing wall mounts and I'm not getting a real warm and fuzzy.

>> Condensing versus non? well a lot of that depends on how much radiation you have. If you dont have enough radiation a condensing boiler will rarely if ever actually condense and give you those high efficiency numbers. Most, if not condensing will run between 87 and maybe 92% plus or minus and you are paying a premium for equipment that never reaches its potential. The truth is that unless money is no object you have to trade off between best efficiency and most cost effective.

I'm not sure what you mean by "depends on how much radiation you have". The 2 active zones are all old cast iron radiators. Some of these are pretty big. We have a 3rd zone w/ baseboards for the rear addition - but that zone is drained out entirely - and we are just using heat pumps there. Does that help to allow you to provide any thoughts?

We're not overly concerned with 84/85 vs 92% efficiency. Our first focus would be Reliablility, less maintenance and long-life, rather than upfront cost of the gear.

Thanks!

Jeff
 

Dana

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A 40-50 gallon hot water heater isn't going to support 4 simultaneous showers + other loads for very long on it's own with only 60K of burner outut underneath it. With drainwater heat recovery 60 gallons could do OK though.

The deal with the newer c.i. Burnhams is that they come with the heat-purge controls and cool return-water boiler protection already installed. The basic boiler underneath it all is pretty antiquated, but well-tested. You can get the same performance out of any number of other cast-iron boilers, but you'd have to design and plumb in the boiler protection and add the heat purge controls. Some consider them little more than dressed up pigs with a lip-gloss finish (which they kinda are), but from a system design & installation simplicity point of view it's a pretty good package, more forgiving than mod-cons. If the fuel were $2-3/gallon propane rather than $1/therm gas the mod-con would pay off in short years. Without the prospect of truly huge fuel price inflation it's hard to push too hard in that direct. I expect we'll see prices climb to an inflation adjusted $1.50/therm in PA over then next decade, but I don't quite see how it'll hit $2 for sustained periods at this point in gas-exploration/production history. (cood b rong, offen am.)

That said, given that your radiation was even able to take a 240 MBH boiler's output, it's probably enough to be in condensing mode 100% of the time now that your heat load is under 60MBH. It was probably designed with some margin for the home's heat load on day 1, a period of coal-fired boilers and people sleeping with the windows cracked to mitigate the risk of carbon monoxide poisoning. If you took the time to measure up all the rads and come up with a square feet of equivalent direct radiation number it's pretty easy to come up with the average water temperature requirements that delivers 50-60K from that radiation. It's very likely to be under 120F, in which case you'll beat 95% with almost anybody's mod-con.
 

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See my comments regarding boosting showering capacity vs. indirect sizing on your other thread.

Words to live by: Never ascribe malice to that which could be explained by ignorance or stupidity.

There's a wealth of ignorance about this stuff in the heetin' ''n' plummin' biz. Back in the day it was common to size the boiler for the peak water heating load, to hell with the average operating efficiency, which is how a lot of older homes ended up with boilers 3-5x oversized for the heat load, but we don't need to repeat those mistakes if we know better.

I'll look for the shower boost piece - there's a lot of info and I'm very grateful to have it!

I don't think that the one guy was intentionally trying to mislead me. I try and go by "trust but verify". Most people are reasonably honest, but they "know what they know". Same in my industry.

But ... some people aren't honest (shocking, I know). A different guy was out here from Harris Fuel. He specs out all the jobs for the local office with 20 techs. They sold the 240K gear 10 years ago to the prior owner, and had her on the hook for all her oil fills as well! He also said that an indirect's load would need to be added in. :p In his case ... I'd bet that he did know better, and they benefit from selling oil, not just equip installs - and they charge .25-40 more per gallon than I paid via COD from other places.

Jeff
 

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Hi Dana,

>> A 40-50 gallon hot water heater isn't going to support 4 simultaneous showers + other loads for very long on it's own with only 60K of burner outut underneath it. With drainwater heat recovery 60 gallons could do OK though.

Gotcha! It would be pretty rare for us to have more than 2 simultaneous showers. This time of year if I shower immediately after Amy, I'm happy the whole time. Our current 50 electric mostly keeps up with all of us, especially May-Oct. In the winter with the colder incoming water it honestly can struggle here and there - and 1 person might have more of a warm but not hot shower. I'd really like to avoid that possibility.

I do savvy that a 40 indirect has much better recovery times than a 50 electric. But it's hard to put my head around what that really means. A fair number of people are saying that a 40 indirect would take care of us. I think that you might have voiced this? The 50 indirects don't seem to cost much more than the 40s. Honstly I would FEEL better having it, even if I knew 100% that it was 10 gallons that we didn't need.

What are your favorite Indirect Water Heaters?


Thanks for mentioning Drainwater heater recovery. It's very cool. I looked into it 2 months back but we can't do it here. Too much of our piping is inaccessible and about 50' from the boiler.


>> The deal with the newer c.i. Burnhams is that they come with the heat-purge controls and cool return-water boiler protection already installed. The basic boiler underneath it all is pretty antiquated, but well-tested. You can get the same performance out of any number of other cast-iron boilers, but you'd have to design and plumb in the boiler protection and add the heat purge controls. Some consider them little more than dressed up pigs with a lip-gloss finish (which they kinda are), but from a system design & installation simplicity point of view it's a pretty good package, more forgiving than mod-cons.

Dana - that Burnham ESC3 sounds SO GOOD. I like that combo of "tried and true cast iron with new tech on top of it" and direct venting through the rear basement wall. I've asked my plumber friend to get a price on one of those through his local distributors. Is this model also "pre-configured" (sorry for my lack of proper hvac-speak) for adding an indirect?

THANKS!!!

Jeff
 

Dana

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A 40 gallon indirect would be fine if it's just 2 showers at a time. With drainwater heat recovery and the 60K output of a ESC3 you could pretty much run 2 simultaneous showers all day long.

But if you really need to run 4 showers concurrently it takes more tank than that- a LOT more if you have people who like long showers.

Adding an indirect is not a function of the boiler's plumbing- the heat exchanger on the indirect is just another heating zone, usually with it's own pump. But you need to use a zone controller that can be configured with a "priority" zone, which suppresses the pumps/valves driving heat to the other zones when the priority zone is called. With the indirect calling for heat you'd really like to take 100% of the boiler's output for the water heater. While this means you won't be actively heating the house whenever the water heater needs the heat, you'll never even notice the pause on the heating system unless she decides to take a 3 hour shower on the coldest morning of the year. :)

The output of the ESC2 is about 2-3x what the heating elements of a 50 gallon electric tank delivers, which means the recovery time is cut by more than half. It's enough output to run a single 1.85gpm shower endlessly at your anticipated incoming water temps, so there is literally no waiting ever with just the two of you showering serially. The problem only comes when you have 4 showers running concurrently for any length of time.

BTW: On the drainwater heat recovery units, EFI's wholesale price is the cheapest I've seen in the US, and anybody can get that price by opening up an account, which can be done over the phone with a credit card. Renewability, the manufacturer also sells direct, but at full retail, which is substantially more.) The biggest one that fits (both diameter and length) is the right one- the marginal cost uptick of the bigger units is smaller than the bigger uptick in performance. I installed a 4" x 48" in my house for showering capacity reasons because it was the largest that fit, and it does the trick! A 3" x 60" has about the same performance, but they make 4" x versions in some very long lengths. EFI only carries a select subset of what's available, but it's a reasonable subset. HomeDepot retails them in a number of lengths, but are often "internet only", you'd have to have it shipped, and the price/performance isn't quite as good. To compare apples to apples Natural Resources Canada maintains a list showing the efficiency of third-party tested units at 2.5gpm flow here.
 

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>> A 40 gallon indirect would be fine if it's just 2 showers at a time. With drainwater heat recovery and the 60K output of a ESC3 you could pretty much run 2 simultaneous showers all day long.

(Shhhhh!) She'll HEAR YOU! :)

>> Adding an indirect is not a function of the boiler's plumbing- the heat exchanger on the indirect is just another heating zone, usually with it's own pump. But you need to use a zone controller that can be configured with a "priority" zone, which suppresses the pumps/valves driving heat to the other zones when the priority zone is called. With the indirect calling for heat you'd really like to take 100% of the boiler's output for the water heater.


Dana - I do get the basic notion of "the indirect gets priority". But I'm having a tough time grasping "the stuff that needs to be installed to make that happen".
Assuming an ESC3 as the boiler - would you please be so kind to outline this - that would get through my thick skull?


>> While this means you won't be actively heating the house whenever the water heater needs the heat, you'll never even notice the pause on the heating system unless she decides to take a 3 hour shower on the coldest morning of the year. :)

Very clear - thanks! Piece of mind is nice - a hot shower ... priceless!


>> The output of the ESC2 is about 2-3x what the heating elements of a 50 gallon electric tank delivers, which means the recovery time is cut by more than half. It's enough output to run a single 1.85gpm shower endlessly at your anticipated incoming water temps, so there is literally no waiting ever with just the two of you showering serially.

That will be just GREAT! Perfect!


>> BTW: On the drainwater heat recovery units, EFI's wholesale price is the cheapest I've seen in the US, and anybody can get that price by opening up an account, which can be done over the phone with a credit card.

Perhaps this should be posted in a new thread, for others to find? I can't do it but others will be able to take advantage.
 

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Hi Dana and Tom,

Here's some stuff I've found on US Boiler / Burnham. Interestingly they are based right here in PA. So I would have to believe that it would be easy to get parts etc. But their BBB rating isn't great and they aren't accredited.

Most of the bad reviews are from products other than their ESC series - I guess that serious is pretty new, so maybe we won't know anything about their reliability for a while to come. Do I have reason to be nervous about the ESC3 or what warranty I'll actually get from them - if something happens?

For us, Reliability is the single most important thing. Thanks!

The BBB link "is what it is". The other two ... I'm thinking they could both just be fake sites. They just don't feel like really legitimate review sites to me. The "heat pump" section doesn't even include fujitsu, mitsubishi or lg :)

http://www.bbb.org/washington-dc-ea...roducers/burnham-llc-in-lancaster-pa-70001223

http://www.furnacecompare.com/boilers/burnham/reviews/

http://www.hvac-for-beginners.com/boiler-ratings.html

Thanks!

Jeff
 
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jefferson17

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Dana,

Well I'll be DAMNED! I got a hold of Slant Fin's heat loss calculator and very carefully went through it.

With an inside temp of 70 and design temp of 15, I get a heat loss of 55,245. And this is probably still at least a bit high by perhaps 3-5K, since I couldn't tell it effectively about the spray foam in the walls on the 2nd floor or the air sealing and insulating spray foam in the rear addition.

Wow! What an eye-opener!

Jeff
 

Dana

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Yep- the real heat loads are a lot lower than most people think they are.

BTW: I realized that I had not clicked-off the hot-water use selector when I ran the FSA. Re-running it using the ~84% efficiency 150K boiler with the very low standby (but no heat purge) model most similar to (but still substantially smaller than) yours, with 1200 gallons /year usage it came in at 60,000BTU/hr @ +10F, and at 1000 gallons/year it comes in at 49,000BTU/hr @ 10F.

If I bump the output of that boiler model to 200,000 BTU/hr to make it more closely approximate yours, the 1000g/yr spits out 48K @ 10F 1200g/yr yields 58.6K @ +10F.

Given those modeled numbers @ +10F, and the fact that the SlantFin tool is saying 55K @ +15F, I'm inclined to believe your heat load is probably well under 50K, closer to 45K @ +15F. You won't be cold with a 70K-in/60K-out boiler even at +5F outdoor temps, but below 0F it might start losing a bit of ground. Assuming a 65F balance point and a 45-50K heat load at 15K thats 900-1K of boiler output required per degree below 65F. But as you continue to knock the load down with air sealing & insulation you will continue to buy margin.

When stepping down that much in boiler size and with high-mass radiation you can't use really deep overnight temperature setbacks as an economizing strategy. But some of the "learning" thermostats like he Nest figure out when you need the house to be at a certain temp, and calculate the warmup ramps pretty well. It's probably not the first place to spend the money, but they can be pretty nice once you've buttoned up the house and have the new boiler setup dialed in, and would probably save at least 50 therms/year, but probably not 100 unless you're out of the house a lot.

Complaints about cracked or rusting boilers not getting full warranty treatment after 10+ years of service need to be taken with a grain of salt. Many of those types of issues can be a result of improper installation that may have lacked adequate cool return water protection. Ignition system failures can often be traced to short-cycling due to gross oversizing for the amount of radiation (particularly on multi-zoned systems.) If you look at the negative reviews of any manufacturer's boilers the theme is similar cracked or leaking after x years of service, ignition crapped out in only y ears, but without details about the installation it's hard to say if the fault lies with the manufacturer or the installer. Installer training is often woefully lacking- and folks with plumbing skills aren't automatically hydronic system designers, but often have enough information to be dangerous for getting the full lifespan out of the equipment. It's not uncommon to see a cast iron boiler succumb to condensation from cool return water in 1-2 seasons due to improper system design/installation. But the installer is more likely to blame the manufacturer, replaces the same equipment without changing the system plumbing (charging "labor only") just to have it fail again in 1-2 years, leading the homeowner to launch bitter "lousy manufacturer, went through three boilers in just five years" kinds of complaints. The odds of an established manufacturer's boiler design or quality control being that bad are infinitesimally remote. Odds of something being amiss in the system design or commissioning tweaks are pretty high.

That's why you will want to plumb in a system by pass loop with ball valves and tweak the return water up to 110F a few minutes into a cold start. Even though the ESC series tolerates 110F return water. It WON'T tolerate 90-100F return water on a regular basis, but it would take awhile for the failure to occur, and you have enough radiation with enough emittance & mass that it's likely that direct-pumped with no radiation bypass you'd be getting a lot of sustained sub-110F return water events during the shoulder seasons, when the radiators can actually cover the load at 110F.
 

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In forty years of doing this I can honestly say that I have only run into two boilers that were absolute crap. One from Slant Fin and the other from Burnham. I'll admit to haveing favorites and that some are easier to service than others but properly installed 99% of them will outlast their warranty by decades.
 

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Can we assume those are models no longer offered?

I've seen plenty of the low end ~78% AFUE Burnham P20x series (now set up to run 82%) with 25+ years on 'em (not that I'd go out of my way to buy one.) I even scrapped one fully functioning with only ~15 years of service on it due to gross oversizing, when I got around to dealing with the system at the house where I'm currently living. The thermocouple on the standing pilot needed replacing at about age 12 (no bfd- expected, in fact), and the automatic flue damper developed an intermittency due to a cold solder on the printed circuit board at about the same time, which I repaired by reflowing the solder rather than replacing the unit. The basic boiler underneath had no issues, looked clean, burned cleanly. I didn't test the combustion efficincy, but it was probably still hitting around 80%. The ES2 & ESC series are probably not that different underneath the fancier controls and new tin, but I don't know that for sure. The 3-section Burnham PVG (same output & efficiency specs as the ESC) in my nieces place has about 5 years on it now (running ~130-135F return water) with no detectable signs of problems. I'd expect something in the controls or maybe the blower to maybe get funky by age 20-25, but those are component-swap repairs.
 

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Hi Dana,

>> Yep- the real heat loads are a lot lower than most people think they are.

I know that you have some very fancy tool - and I'm guessing that normal folk like me don't have access to it. I had a thought - would you consider looking at that spreadsheet that I used before? I bet it wouldn't take all that much time, to tweak it up and make it much more accurate than it is now. Even if it is designed to be a touch conservative, that would be much better than the additional 20K BTU (36% oversized). People could REALLY use a GOOD and easy to use tool. There's not much out there today. What do you think?


>> When stepping down that much in boiler size and with high-mass radiation you can't use really deep overnight temperature setbacks as an economizing strategy. But some of the "learning" thermostats like he Nest ... It's probably not the first place to spend the money ... but they can be pretty nice once you've buttoned up the house and have the new boiler setup dialed in, and would probably save at least 50 therms/year, but probably not 100 unless you're out of the house a lot.

More excellent info? Is there any end to your knowledge and helpfulness? :) This is great stuff. Given our situation, and how our zones are piped, I only drop the Night temp to say 67 from 70. I bought several programmable Lux thermostats (m-f, sat, sun) w/ wake, away, back, night) 4 years ago. They are nice for $35 and great compared to the super old dial types that were still here!

Yeah sounds good. Those basement band joists need some attention and I've got lots of uninstalled soft fiberglass ceiling tiles that need a new home!

>> Complaints about cracked or rusting boilers not getting full warranty treatment after 10+ years of service need to be taken with a grain of salt. Many of those types of issues can be a result of improper installation that may have lacked adequate cool return water protection. Ignition system failures can often be traced to short-cycling due to gross oversizing for the amount of radiation (particularly on multi-zoned systems.) If you look at the negative reviews of any manufacturer's boilers the theme is similar cracked or leaking after x years of service, ignition crapped out in only y ears, but without details about the installation it's hard to say if the fault lies with the manufacturer or the installer. Installer training is often woefully lacking- and folks with plumbing skills aren't automatically hydronic system designers, but often have enough information to be dangerous for getting the full lifespan out of the equipment. It's not uncommon to see a cast iron boiler succumb to condensation from cool return water in 1-2 seasons due to improper system design/installation. But the installer is more likely to blame the manufacturer, replaces the same equipment without changing the system plumbing (charging "labor only") just to have it fail again in 1-2 years, leading the homeowner to launch bitter "lousy manufacturer, went through three boilers in just five years" kinds of complaints. The odds of an established manufacturer's boiler design or quality control being that bad are infinitesimally remote. Odds of something being amiss in the system design or commissioning tweaks are pretty high.

Your point is VERY well made indeed. So there are lots of homeowners who think "hey this is a garbage boiler" when the likely root cause of a failure or short life span is a bad install / no adjustments to ensure proper return temps, etc. This makes a LOT of sense! Thanks!



>> That's why you will want to plumb in a system by pass loop with ball valves and tweak the return water up to 110F a few minutes into a cold start. Even though the ESC series tolerates 110F return water. It WON'T tolerate 90-100F return water on a regular basis, but it would take awhile for the failure to occur, and you have enough radiation with enough emittance & mass that it's likely that direct-pumped with no radiation bypass you'd be getting a lot of sustained sub-110F return water events during the shoulder seasons, when the radiators can actually cover the load at 110F.[/QUOTE]

Dana: I know you are saying something really IMPORTANT here but I also know that I'm not really following it well enough.

Ultimately it's OUR boiler and we need to know that the heating system including valves etc are tweaked to ensure that our boiler has a long and reliable lifespan.

Let's please assume an ESC3 with Burnham's 50g indirect (only $120 more than their 35g). We'll get $300 back afterwards for the boiler. We'd be CRAZY to do a gas conversion.


When you talk about a cold start - is that only just the start of the season?

I'm not following what you mean about "plumbing in a system bypass loop with ball valves and tweak the return temp to 110 on a cold start". I sorta have a GUESS about what your intentions might be but I'm hoping you have one of your amazing diagrams??? (hint, hint).


RUNNING HEALTH DURING SEASON?
After it's up and running, it sound like I must simply make sure the return pipe back to the boiler is at LEAST above X. I can easily measure that. Is that 120? 130? I'm good at doing what I'm told - just ask Amy :)

The currently 2 active zones all have cast iron rads, and all valves are set to wide open. I believe that these will need to be adjusted down - to slow the rate of flow. Is this correct? Is there a good process to follow? I would think that I'll need to keep checking daily for the first 1-2 weeks then perhaps only weekly for the next few months - to tweak it if need be.

THANKS SO MUCH!
 

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The fancy tools I personally tend use for first-cut heat loads are standard spreadsheets, and I'll calculate the U-factors from engineering tables. Most tools aren't dramatically different from that behind the user interface, but have a limited range of U-factors. The pro-tools have better range of pre-calculated U-factors and take a stab at site-factors for solar gain, etc but the biggest error in any of these methods tends to be in the infilration/ventilation rates.

The important issue about cold start protection:

In the beginning, you have something on the order of 500-1000lbs water-equivalent thermal mass of radiator-iron & water at about 65-68F. Can't estimate the real thermal mass without a better description of the radiator and plumbing sizes, but we'll run with 1000lbs for now. It might be as little as half that, but it might be more. If this was originally a gravity-feed coal fired system with 4"-6" plumbing it's going to be a lot MORE than 1000 lbs.

With 60,000 BTU/hr of boiler output, that's (60K/60 minutes=) 1000 BTU/minute, which is plenty for heating up just the boiler from 65F to 110F in short time- a few 10s of seconds probably less than two minutes. But to raise the 1000 lbs of system mass the 40F degrees from 70F to 110F takes (1000 lbs x 40F =) 40,000 BTU, and at 1000 BTU/minute that's a 40 minute burn at sub-110F return water, ignoring for the moment the heat being given up from the radiators to the room. When it's only 45-50F out you'll have a real heat load, but that load is a fraction of what it is at +15F, and it's quite likely that the radiators will emit sufficient heat to satisfy the thermostat without the radiators themselves reaching 110F, which means the return water will be under 110F, and damaging to the boiler.

This is a standard problem with multiple solution approaches, boiler bypass and radiation bypass loops being tried & true standbys. One variation of radiation bypass looks like this:

15214.gif


In this configuration the system pump is pumping toward the bypass loop. A ball valve located where the valve marked "differential pressure bypass valve" is enough, since yours is a one-zone radiation system, and the flow isn't changing. Closing the ball valve would mean 100% of the pumped volume is going toward the radiators, and 100% of the return water entering the boiler is coming from said radiators. If you crack open the ball valve a bit boiler output water is mixes in with that cool return water, raising the temp of the water entering the boiler. Open it up more, the temp of the water entering the boiler rises. The size of the plumbing on that branch loop needs to be substantial but it really depends on he pumping head of the entire system. A 1" diameter bypass branch might cut it, but maybe not ona super low-head system. A real hydronic designer would do the math on the system's pumping head and the pump volume, etc, but most boiler installers would go with whatever worked the last time. A 1.5" bypass plumbing would likely be more than enough, but wide open you may get almost no flow to the radiation- it has to be dialed so that even with a large slug of cool water in the system the temp at the return port on the boiler stabilizes above 110F in the first 5 minutes or so.

Rather than a ball valve (=cheap) this can be implemented with a thermostatic mixing valve (= less cheap) at the intersection of the radiation return and bypass branch and often is, if higher temps are required on the radiation on design day, but I'm going to presume based on just a WAG that you'll never need to hit even as high as 140F at the rads. With the flow split a fixed 50/50 between radiation and bypass at a 70F cold start you'll get your 110F water with the boiler output at 150F you'd have, a sane, comfortable 40F delta-T on the boiler, and as the system temp rises that delta-T will vary a bit as the delta-T across the radiation first shrinks to something like 20-30F with higher temp return water. When the radiation is returning 120F water and the boiler output creeps up the delta-T on the boiler will shrink a bit too. Getting the pump sizing right so this all works, delivers the heat while keeping the delta-T on the boiler under 50F (the likely max operating limit- didn't look it up) under all circumstances is a key part of the design too, but probably not hard to hit. I don't know if that boiler comes with a pump pre-installed, but if it does you may or may not need to swap it depending on your actual system design. (60KBTU/hr with a 40F delta-T is ~3 gpm- you may need it to be more like 4-6gpm starting at a lower delta-T, feeding more boiler of the boiler output back in the bypass to achieve your 110F+ cold start.)

Dead-cold system starts will happen multiple times per year, and tepid-starts will be the norm during the shoulder season. If you tweak the bypass flow such that the mix of return water and boiler output is above 110F a few minutes into a cold start, it'll be above 110F pretty much all the time, and you won't destroy the boiler. With most gas boilers you'd want to set that to 130F+, but the internal plumbing on the ESC takes care of it from 110F & up.

But getting it there is up to the system designer- if that's going to be YOU, it's time to start reading up on it. These tend to not be design-by-web-forum kinds of projects. You have pretty good idea of the heat load, and if you measure up your radiation you'll be able to get a pretty good idea of what your max water temps on the system need to be, and how you need to design the flows to meet all boundary conditions. It doesn't have to be modeled to the n-th degree to work, but it takes more than a coupla napkins and a crayon to get there, and it will take tweaking & measuring while commissioning the system to ensure you don't run into condensation trouble.

If you're plumbing it in yourself it doesn't hurt to add some thermometers on both the output and return ports to the boiler. Otherwise using a wrap of hockey tape on the bit of plumbing where you want to know the temp for spot-checking with an infra-red thermometer makes it easy-it'll be accurate enough for your purposes.

Unless you have two thermostats and two pumps, the adjustable valves you have are there for adjusting the flow to balance the temperatures between what you're calling "zones". In general you'd want one to be wide open, the other throttled back just enough that the temperatures in the different parts of the house served by the two radiator loops track reasonable.
 

Tom Sawyer

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Long since gone. The Burnham was the Fiesta. Steel boiler with a tankless coil in the top that would leak at the gasket and rot the boiler out. I can't recall the slant fin boiler but it was a 2 section, wet base cast iron with a carlin 100 crd in it.
 

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Hi Dana,

Once again – THANK YOU! You are so incredibly helpful and I can't stress enough how thankful we are to benefit from your expertise and knowledge!

The fancy tools I personally tend use for first-cut heat loads are standard spreadsheets, and I'll calculate the U-factors from engineering tables. Most tools aren't dramatically different from that behind the user interface, but have a limited range of U-factors. The pro-tools have better range of pre-calculated U-factors and take a stab at site-factors for solar gain, etc but the biggest error in any of these methods tends to be in the infilration/ventilation rates.

For grins and giggles I did a rework that way and came up w/ a heat loss of just under 50K – including the entire 1000 sq ft basement not only the original section.

Here's kinda a dumb question. Is is appropriate or potentially useful for me to re-work my heat loss to not count the addition in the back – which uses only the dedicated Fujitsu heat pumps (12K BTU per room with shared 24K condenser) for each of the 2 family rooms (one on top of the other – above the rear basement addition underneath them)?

Or is it better to include the rear addition in a total heat loss calculation, regardless that it has its own heating system (but the addition isn't “closed off” and some heat will make it's way from the original Victorian section through doorways and such)? There is 2 feet of solid masonry between the original section and the addition. The 1st level has a single doorway connecting to the rear addition: 36x84. There are 2 picture windows there that are incredibly well sealed - they are nearly soundproof. If we close that one door almost nothing gets through. The other area, 2nd floor, has 2 doorways connecting them – same dimensions: big single french doors w/ 15 panes in each.

The important issue about cold start protection:

In the beginning, you have something on the order of 500-1000lbs water-equivalent thermal mass of radiator-iron & water at about 65-68F. Can't estimate the real thermal mass without a better description of the radiator and plumbing sizes, but we'll run with 1000lbs for now. It might be as little as half that, but it might be more. If this was originally a gravity-feed coal fired system with 4"-6" plumbing it's going to be a lot MORE than 1000 lbs.

With 60,000 BTU/hr of boiler output, that's (60K/60 minutes=) 1000 BTU/minute, which is plenty for heating up just the boiler from 65F to 110F in short time- a few 10s of seconds probably less than two minutes. But to raise the 1000 lbs of system mass the 40F degrees from 70F to 110F takes (1000 lbs x 40F =) 40,000 BTU, and at 1000 BTU/minute that's a 40 minute burn at sub-110F return water, ignoring for the moment the heat being given up from the radiators to the room. When it's only 45-50F out you'll have a real heat load, but that load is a fraction of what it is at +15F, and it's quite likely that the radiators will emit sufficient heat to satisfy the thermostat without the radiators themselves reaching 110F, which means the return water will be under 110F, and damaging to the boiler.

This is a standard problem with multiple solution approaches, boiler bypass and radiation bypass loops being tried & true standbys. One variation of radiation bypass looks like this:

15214.gif


In this configuration the system pump is pumping toward the bypass loop. A ball valve located where the valve marked "differential pressure bypass valve" is enough, since yours is a one-zone radiation system, and the flow isn't changing. Closing the ball valve would mean 100% of the pumped volume is going toward the radiators, and 100% of the return water entering the boiler is coming from said radiators. If you crack open the ball valve a bit boiler output water is mixes in with that cool return water, raising the temp of the water entering the boiler. Open it up more, the temp of the water entering the boiler rises. The size of the plumbing on that branch loop needs to be substantial but it really depends on he pumping head of the entire system. A 1" diameter bypass branch might cut it, but maybe not ona super low-head system. A real hydronic designer would do the math on the system's pumping head and the pump volume, etc, but most boiler installers would go with whatever worked the last time. A 1.5" bypass plumbing would likely be more than enough, but wide open you may get almost no flow to the radiation- it has to be dialed so that even with a large slug of cool water in the system the temp at the return port on the boiler stabilizes above 110F in the first 5 minutes or so.

Rather than a ball valve (=cheap) this can be implemented with a thermostatic mixing valve (= less cheap) at the intersection of the radiation return and bypass branch and often is, if higher temps are required on the radiation on design day, but I'm going to presume based on just a WAG that you'll never need to hit even as high as 140F at the rads. With the flow split a fixed 50/50 between radiation and bypass at a 70F cold start you'll get your 110F water with the boiler output at 150F you'd have, a sane, comfortable 40F delta-T on the boiler, and as the system temp rises that delta-T will vary a bit as the delta-T across the radiation first shrinks to something like 20-30F with higher temp return water. When the radiation is returning 120F water and the boiler output creeps up the delta-T on the boiler will shrink a bit too. Getting the pump sizing right so this all works, delivers the heat while keeping the delta-T on the boiler under 50F (the likely max operating limit- didn't look it up) under all circumstances is a key part of the design too, but probably not hard to hit. I don't know if that boiler comes with a pump pre-installed, but if it does you may or may not need to swap it depending on your actual system design. (60KBTU/hr with a 40F delta-T is ~3 gpm- you may need it to be more like 4-6gpm starting at a lower delta-T, feeding more boiler of the boiler output back in the bypass to achieve your 110F+ cold start.)

Dead-cold system starts will happen multiple times per year, and tepid-starts will be the norm during the shoulder season. If you tweak the bypass flow such that the mix of return water and boiler output is above 110F a few minutes into a cold start, it'll be above 110F pretty much all the time, and you won't destroy the boiler. With most gas boilers you'd want to set that to 130F+, but the internal plumbing on the ESC takes care of it from 110F & up.

But getting it there is up to the system designer- if that's going to be YOU, it's time to start reading up on it. These tend to not be design-by-web-forum kinds of projects. You have pretty good idea of the heat load, and if you measure up your radiation you'll be able to get a pretty good idea of what your max water temps on the system need to be, and how you need to design the flows to meet all boundary conditions. It doesn't have to be modeled to the n-th degree to work, but it takes more than a coupla napkins and a crayon to get there, and it will take tweaking & measuring while commissioning the system to ensure you don't run into condensation trouble.

If you're plumbing it in yourself it doesn't hurt to add some thermometers on both the output and return ports to the boiler. Otherwise using a wrap of hockey tape on the bit of plumbing where you want to know the temp for spot-checking with an infra-red thermometer makes it easy-it'll be accurate enough for your purposes.

Unless you have two thermostats and two pumps, the adjustable valves you have are there for adjusting the flow to balance the temperatures between what you're calling "zones". In general you'd want one to be wide open, the other throttled back just enough that the temperatures in the different parts of the house served by the two radiator loops track reasonable.

AH! I think I “get it” now! That is GREAT – THANKS! For us, a Solid, Simple, and Idiot-Proof (me) design is best with one of your fancy thermostatic mixing valves. I shouldn't be in the mix - something bad/expensive would eventually happen. It's much better to have some good technology protecting our boiler automagically, avoiding cold water shock so that it has a long life.

I had another heating guy come out here the other day and he was the ONLY out of the bunch who mentioned that this should be done to protect the boiler. He also suggested we get a circulation pump to keep the hot water (shower water) from the new indirect water heater up to the front of the house, so that people wouldn't have to wait any longer than they do now for hot water to the showers (extra 50' or so in ¾ pex). That made sense to me and once I figure out what to buy I'll get one and plumb it in w/ Pex, and put in a dedicated return ¾ Pex, so that we don't end up with warm water in the cold pipe.

The ESC3 lists it's input/output pipes as 1.25”. Does the thermostatic protection valve need to also be 1.25 or can it be say 1” or 3/4”? My GUESS is that any pipe that handles the flow rate is still ok but that's just a guess and I wouldn't want some inspector to fail me, if I chose the wrong thing.

Some (most) of the 1.25 models seem pretty expensive but I want to do the “right thing” here. I've found a few things and would appreciate advice as to what models might be a good fit for the ESC3.

It's really hard for a layman (and calling myself that is generous) to know what is or isn't proper. THANKS! Are ANY of these appropriate for the ESC3? If not, I'd love a few recommendations and I'll just buy one.

http://www.pexsupply.com/Tekmar-712-1-1-4-Brass-3-Way-Mixing-Valve-4866000-p

http://www.pexsupply.com/Honeywell-Sparco-AM102-US-1LF-1-Sweat-Union-Mixing-Valve-Lead-Free

http://www.amazon.com/Honeywell-V80...=1-1-spell&keywords=thermostatic+boiler+valve

http://www.amazon.com/ThermoMix-Hig...339&sr=1-1&keywords=thermostatic+boiler+valve

>> Unless you have two thermostats and two pumps, the adjustable valves you have are there for adjusting the flow to balance the temperatures between what you're calling "zones". In general you'd want one to be wide open, the other throttled back just enough that the temperatures in the different parts of the house served by the two radiator loops track reasonable.

Yes we do – 2 zones each w/ it's own thermostat and pump. There is a 3rd zone but it may never see use again, unless the heat pumps have an issue.

THANKS very very much!

Jeff
 

Dana

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The boiler is best sized for the loads it is actually serving, so the zones served by the mini-splits need not be include in the calculation even if you hook up those baseboards to the system as backup.

With two circulation pumps it's usually awkward to implement a radiation-bypass loop, and you'll often have to resort to other methods of boiler protction, such as boiler-bypass. In a boiler bypass configuration it pumps away from the bypass branch rather than toward is. This is somewhat less protective than radiation bypass, but can usually still get the job done. A key thing to get right on the boiler bypass is to deliver the minimum flow requirements for the boiler under all conditions so that the delta-T on the boiler itself stays withing spec. (A 60K boiler with a 50F max delta-T needs about 2.5 gpm as the absolute minimum.)

resize_ByPassValve.png


In the event that you are so over-radiated for the load that the water temps are too low to meet the return water flow & temp requirements with a boiler bypass you may need to add a pump and set it up primary/secondary loops which is also a standard way to deal with it:

114614.gif


A number of system architectures can work, but to figure out the most optimal scheme in YOUR case requires knowing the heat load, the total radiation size, and the boiler output, from which all temperatures and pumping requirements can be determined. An unsophisticated installer who either doesn't understand that it's necessary or ignores the particulars can screw it up royally without half trying, which is why it's good to have a handle on it ahead of time to vet their choices. Don't be afraid to ask them which configuration they're going with and why. (You might even convince them to actually do the math this time! :) )

If you use a thermostatic valve on the bypass loop it's OK to go with 1" (or even 3/4") rather than 1.25", provided it's rated for the both min & max flows you actually pump. The pumping head presented by the valve itself is relatively low, but if the radiation flows need to be exceptionally high pumping a high velocity through the thermostatic valve may become an issue (don't go with a 1/2" version.) There are probably several suitable 1" 3-way mixing valves that would do it.
 
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