Steam Boiler Sizing, Small Home

nicholas bonham-carter

I would suggest reading the steam books available here to gain knowledge of how our wonderful old steam systems should be installed.
Beyond that, we can only offer sympathy, and advice on coping mechanisms to deal with improper installations.
BirchLeaf, what symptoms had you noticed, which lead you to a conclusion that something was wrong with your system?
In a system which is short-cycling, I would suggest generous main venting to get the air out as quickly as possible and fill the supply pipes with steam first, on each cycle. Slow radiator vents will help.—NBC 

Grallert

Jamie Hall said:

BirchLeaf said:

@Jamie Hall I will try that. He should remove the boiler and put one that's the correct  size. He failed to properly size this one and the warranty won't cover problems caused by improper sizing.

Aye, he probably should. He probably won't. So... the question really is do you want to beat your head on the wall, or would it be simpler to see what we can do to get what you have working well? It will, you know. It won't be perfect, but things rarely are. If it were mine at this point, I'd see what I could do along those lines, and let it be. But that's me.

I'm with Jamie and Chris on this. Rattle the cages but try not to let it take over your life. Yes the boiler is oversized. Is it grossly oversized? I don't this so. Where the installers numbskulls? Yes. But all is not lost. Many boilers will operate at various firing rates to accommodate a few different spaces. Correct piping and venting , correct pressure setting and appropriate thermostat setting are more important. You will get good sound advice here.

pecmsg

One option while the boiler is new is to donate it and take the write off. Sometimes it works out in your favor. 

BirchLeaf

@ethicalpaul I called them today, told them my radiators are extremely hot. One of the guys came over and lowered the pressure on the boiler from 3.5 to 2.
He's coming back tomorrow to see if it helped.
Also, asked him if any way to reduce the square footage of steam coming from boiler. He said, yes, by removing one of the tubes.

ChrisJ

BirchLeaf said:

@ethicalpaul I called them today, told them my radiators are extremely hot. One of the guys came over and lowered the pressure on the boiler from 3.5 to 2.
He's coming back tomorrow to see if it helped.
Also, asked him if any way to reduce the square footage of steam coming from boiler. He said, yes, by removing one of the tubes.

Oh the manufacturer will absolutely love that.

@JohnNY Can you give your opinion on the situation?

JohnNY

@ChrisJ Must I? There's so much wrong in that statement I wouldn't know when to stop typing.

veteransteamhvac

Extremely "hot" radiators.

KC_Jones

BirchLeaf said:

@ethicalpaul I called them today, told them my radiators are extremely hot. One of the guys came over and lowered the pressure on the boiler from 3.5 to 2.
He's coming back tomorrow to see if it helped.
Also, asked him if any way to reduce the square footage of steam coming from boiler. He said, yes, by removing one of the tubes.

If you are worried about warranties, like you stated before, that is a sure fire way to have it invalidated. No manufacturer is going to warranty it if anything goes awry. Now, there are some boilers that actually have 2 different burners available with the same block. In those cases, if they replace the entire burner array and any other components (draft hood may be one), then yes the boiler could be down fired and be ok with the manufacturer and the warranty. We'd need to know exactly which boiler they installed to comment if that is possible. Pictures of the data plate would help with that.

Speaking of pictures, would you care to post pictures of the install for comment as to whether they piped it correctly? It was mentioned earlier in the thread, but I haven't seen any yet.

Radiators being extremely hot isn't really a criteria here. They get hot, that's what they are supposed to do. If you plan on pushing back on the sizing you are going to have to call that out directly, not hint at it. They sized it wrong, they may not even be aware they did it. We've had professionals come on here admitting to sizing it wrong and not even realize it was wrong until we explained it.

pecmsg

BirchLeaf said:

@ethicalpaul I called them today, told them my radiators are extremely hot. One of the guys came over and lowered the pressure on the boiler from 3.5 to 2.
He's coming back tomorrow to see if it helped.
Also, asked him if any way to reduce the square footage of steam coming from boiler. He said, yes, by removing one of the tubes.

So far, they've sold you an oversized boiler, had it operating at too high a pressure, Claim they can remove a tube to lower capacity (That id like to see)

It's time to cut your losses and find someone that Knows Steam.

Did you ever get pictures as requested?

Erin Holohan Haskell

Dan_NJ said:

Maybe there already is an example of this on the site, but it might be good for readers to have access to a "sample" contract that spells out exactly what should be covered and what is expected of a steam boiler install. To at least have a chance at evaluating various bids and why some are lower than others?

We have that here: https://heatinghelp.com/blog/how-to-find-a-good-steam-heating-contractor/

BirchLeaf

@KC_Jones
You're right. I'm going to have to call them out directly on the oversizing. What do I say to them?
(They never measured or even looked at the radiators. They must know this is necessary. They've been doing it for years.)

EBEBRATT-Ed

@BirchLeaf That's the problem they have been doing it for years and don't know. Get some documentation from the boiler mfg and others places that shows radiation sizes for steam boilers.You can download material from Peerless or the "burnham heating helper" is on line.

KC_Jones

BirchLeaf said:

@KC_Jones
You're right. I'm going to have to call them out directly on the oversizing. What do I say to them?
(They never measured or even looked at the radiators. They must know this is necessary. They've been doing it for years.)

As said, you would first have to convince them they are wrong, that would take documentation. Here is the wording from Weil Mclain boiler replacement guide:

"8. Convert the total square feet of radiation to BTU/Hr. Each square foot of steam radiation is based on a heat emission of 240 BTU/Hr. with standard 70°F air temperature and 215°F steam temperature in the radiator.
9. Size the replacement steam boiler by selecting a unit with a AHRI NET Steam rating equal to or greater than the BTU/Hr. capacity of the radiation."

Link to that guide:
https://www.weil-mclain.com/sites/default/files/field-file/Weil-McLain_BoilerReplacementGuide_WM2012-web_0.pdf

So in your case you are looking for a boiler with a net AHRI rating as close to 48,960 btu's as possible. In reality all the boiler manufacturers give the rating is sq ft of radiation, so you'd be looking for a boiler with a rating as close to 204 as possible.

I don't know which brand they installed, but given it's rated for 321, I am assuming there is one smaller that is a closer match to your system, all the brands I am familiar with have one smaller, some have 2 smaller. If you let us know the brand we could look up the ratings chart.

I wouldn't keep my hopes up, you will be asking them to tear out a brand new boiler and put another one in. They will be very resistant to that and given they already have your money, they don't have much incentive to do anything.

Are you not interested in posting pictures? If they installed it incorrectly that is potentially more leverage to get them to fix things.

JohnNY

Yesterday I visited a home where I installed a vaporstat and a 2-stage GCV on a Burnham Independence residential steam boiler in 2015. It's still doing a great job of providing high-low-high fire. This was such a big thing on The Wall back then. I want to bring it back for our oversized boiler people.

ChrisJ

JohnNY said:

Yesterday I visited a home where I installed a vaporstat and a 2-stage GCV on a Burnham Independence residential steam boiler in 2015. It's still doing a great job of providing high-low-high fire. This was such a big thing on The Wall back then. I want to bring it back for our oversized boiler people.

If the boiler fires good at low fire is there any reason not to just drop the manifold pressure down to that permanently?

Are there concerns with lighting?

We should bring it back if it helps.  Every little bit helps, even if it's not perfect.

I feel this is one of the biggest thing killing steam, and likely hot water is well.  Improper installs and improper maintenance and people spending money and getting bad results.  Many don't mind spending more for a better, more comfortable system but when it just results in worse performance that word gets around to others and it spreads fast.

The average Joe shouldn't need to know how to plumb their own boiler in order to get it worked on.

ethicalpaul

I love the idea, @JohnNY but I had the same question. This homeowner is obviously never going to need "high fire", so if it's safe to run the thing with a low fire/high fire situation, then how can it not be safe to just remove a couple burners?

Does it truly hurt the combustion that much? I've seen all the open space at the bottom of my atmospheric boiler and the giant hole in the draft hood...I can't believe this is a precision instrument.

nde

There is no law against incompetence. Best you can probably do is threaten to sue and then walk away if contractor refuses to make it right. I would post as many 1 star reviews as possible on social media to at least alert future customers.

Having said that oversized boilers are not the end of the world, they are slightly less efficient but the fact is they make more steam faster and therefore run shorter cycles. They are best handled with lots of main venting and a thermostat setting without swings (set and forget). With some vent tweaking I am sure you can make it similar to old unit if the difference really is only 15k btu.

ethicalpaul

The difference is way more than 15k btu in this case. I'm not disagreeing with your advice, those are good things to try, but in the end it's ridiculously oversized.

ChrisJ

nde said:

There is no law against incompetence. Best you can probably do is threaten to sue and then walk away if contractor refuses to make it right. I would post as many 1 star reviews as possible on social media to at least alert future customers.

Having said that oversized boilers are not the end of the world, they are slightly less efficient but the fact is they make more steam faster and therefore run shorter cycles. They are best handled with lots of main venting and a thermostat setting without swings (set and forget). With some vent tweaking I am sure you can make it similar to old unit if the difference really is only 15k btu.

A few years ago I swapped burners in my boiler to decrease it's output.
The reason was having more output meant it was more difficult to control. 5 minutes of heat produced more output than a smaller boiler, so overshoot was difficult to avoid. 5 minutes became 6 minutes, 20 minutes became 24 minutes etc.

With the smaller boiler I have a much easier time controlling it.

Faster isn't better, faster is easier to notice.

KC_Jones

nde said:

There is no law against incompetence. Best you can probably do is threaten to sue and then walk away if contractor refuses to make it right. I would post as many 1 star reviews as possible on social media to at least alert future customers.

Having said that oversized boilers are not the end of the world, they are slightly less efficient but the fact is they make more steam faster and therefore run shorter cycles. They are best handled with lots of main venting and a thermostat setting without swings (set and forget). With some vent tweaking I am sure you can make it similar to old unit if the difference really is only 15k btu.

The installed boiler is more than 50% oversized for the radiation. Not sure where 15k comes from, but it's about percentages. 15k on a 200k system, no big deal. 15k on a 49k system starts becoming a much
bigger deal. In this case it's 28k over, on a system that needs 49k, again more than 50% oversized. The smaller the system, the more critical the sizing becomes.

Don't forget, there is also 33% more in there for the pickup. So the installed boiler has a rating of 321, if we add the pickup to that it's gross output would be 426, the system is 204, that leaves a pickup of 222, which is 108% pickup factor. Again, it's grossly oversized.

Venting will only get you so much, after the 2-4 minutes it takes to vent the mains, it's onto the rad vents, then pressure builds which does no good at all.

BirchLeaf

@KC_Jones That's the same guide (Weil-McLain) I used to figure the EDR for my home.
When they were done installing, they let me know and I went down to look with them. That's when I learned it was 125,000 btu output. I said that's too high, you said you'd match what I had (112,500). He said they don't make that size anymore; that there was a 100,000 available. I said you should have installed that one and he responded that they couldn't go lower than what I had before. (All of this, of course, is before learning what I know now.)
I also see the company has a 75,000.
I'd rather not post pics.

BirchLeaf

@ethicalpaul I asked him if possible to lower steam sq. ft. coming from boiler. He said they could remove one of the tubes. Is this "tube" a burner, do you think?

FYI - My previous boiler was 112,500 (it was fine, but realize now could have been smaller). New boiler is 125,000.

ChrisJ

BirchLeaf said:

@ethicalpaul I asked him if possible to lower steam sq. ft. coming from boiler. He said they could remove one of the tubes. Is this "tube" a burner, do you think?

FYI - My previous boiler was 112,500 (it was fine, but realize now could have been smaller). New boiler is 125,000.

Please give us some pictures of the install.
I downsized my WM boiler from 150K input to 125K input and I did it by swapping the parts necessary.
BUT this was only possible because WM's EG-40 and EG-45 literally are the same boiler minus a few changes in the burner and drafthood assembly.

I couldn't just remove a tube.

But, let's see what you have and we'll see how we can help.

pecmsg

BirchLeaf said:

I'd rather not post pics.

Why?

ChrisJ

pecmsg said:

BirchLeaf said:

I'd rather not post pics.

Why?


Yeah,
Without pictures I feel like this is a giant waste of time.
If the thing is piped terribly than there's absolutely no point in trying to come up with a possible work around.

KC_Jones

BirchLeaf said:

@KC_Jones That's the same guide (Weil-McLain) I used to figure the EDR for my home.
When they were done installing, they let me know and I went down to look with them. That's when I learned it was 125,000 btu output. I said that's too high, you said you'd match what I had (112,500). He said they don't make that size anymore; that there was a 100,000 available. I said you should have installed that one and he responded that they couldn't go lower than what I had before. (All of this, of course, is before learning what I know now.)
I also see the company has a 75,000.
I'd rather not post pics.

He should have said the wouldn't go lower, they absolutely could have. It's the typical attitude of bigger is better, which is actually incorrect.

KC_Jones

pecmsg said:

BirchLeaf said:

I'd rather not post pics.

Why?

Agreed, why?

Honestly, the piping is more important than the sizing, but with an oversize boiler it becomes even more critical. With improper sizing, and the comments they have made to you so far, I would speculate the piping is incorrect as well, given how much else they don't seem to understand, but without pictures we are just speculating.

ethicalpaul

Just to be clear, you did pay them, right? Did you use a credit card for any of it? You can put in for a claim against that part if you did.

ethicalpaul

Also I find it very weird that they're unwilling to install the correct size boiler, but they are offering to remove a burner tube from the oversized one.

And to finally answer your question, yes, that's what I think they are suggesting, to remove and cap off a burner. Which I would definitely attempt if it were my boiler and I were stuck with it.

JohnNY

@ChrisJ and @ethicalpaul I believe light-off with a reduced volume of gas flow could potentially be problematic at times, but I'm not going to pretend to know that for sure. It's really quite rewarding watching the burner tray in an atmospheric boiler alternate between high and low fire based on steam pressure. It's an expensive thing to do though: replace the gas valve, add a vaportstat, etc. I have a customer who calculated his own orifice sizes on a brand new boiler, drilled holes in blank orifices and replaced them. I find this slightly more concerning.

ChrisJ

JohnNY said:

@ChrisJ and @ethicalpaul I believe light-off with a reduced volume of gas flow could potentially be problematic at times, but I'm not going to pretend to know that for sure. It's really quite rewarding watching the burner tray in an atmospheric boiler alternate between high and low fire based on steam pressure. It's an expensive thing to do though: replace the gas valve, add a vaportstat, etc. I have a customer who calculated his own orifice sizes on a brand new boiler, drilled holes in blank orifices and replaced them. I find this slightly more concerning.

Me too,
There's no way you can "drill" a precision hole. It needs to be drilled and then reamed correctly to size.


But I suspect that's not what you're concerned about.

EBEBRATT-Ed

Not so sure about the drilling and reaming. lol Ever installed a Carlin 201 power gas burner? They are shipped with a 1/2" nipple that has an orifice welded into the nipple half way down. Not knowing what the final burner input will be they ship the burner with a small hole in the orifice.

When you get the burner to the job you look up the hole size needed, grab a drill bit from the nearest hardware store and drill it out. Your usually drilling a 1/2" or maybe a 9/16 hole in it. But with multiple orifices in a residential furnace or boiler this could be an issue. Not all things are precision or need to be.

ChrisJ

EBEBRATT-Ed said:

Not so sure about the drilling and reaming. lol Ever installed a Carlin 201 power gas burner? They are shipped with a 1/2" nipple that has an orifice welded into the nipple half way down. Not knowing what the final burner input will be they ship the burner with a small hole in the orifice.

When you get the burner to the job you look up the hole size needed, grab a drill bit from the nearest hardware store and drill it out. Your usually drilling a 1/2" or maybe a 9/16 hole in it. But with multiple orifices in a residential furnace or boiler this could be an issue. Not all things are precision or need to be.

The burner tubes on my WM are 25,000 btu/h each.
With a 3.5" manifold pressure a 0.098" hole gives 24384 btu/h and a 0.0995" hole gives 25137 btu/h.

That being said, and I know most here already know.
But no one should be modifying these burners without knowing what they're doing and at an absolute minimum having a combustion analyzer to prove the results and that it's burning correctly and not impinging.

BirchLeaf

KC_Jones said:

Weil Mclain EG-30 has an input of 75,000 BTU and is rated for 196 sq ft of steam, it would be a very good fit to your radiation.

That is just one example to give you an idea based on your question, but as said already, don’t make it more complicated than it needs to be.  The manufacturers have ratings for EDR, use those for sizing.

@KC_Jones I calculated 204 EDR for my home. Would 196 sq ft of steam be okay?

KC_Jones

I am of the opinion it will be just fine.  You will still have 26% pick up factor.

pecmsg

Seeing how there's a small % for the piping I don't think there's an issue with a Properly installed and set up 196 EDR unit. It certainly will have better run times.

mattmia2

EBEBRATT-Ed said:

Most states have no code for residential heating installations and if they do they seldom enforce it.

Virtually all mechanical codes have a clause that says equipment must be installed following manufacturer's instructions.

BirchLeaf

mattmia2 said:

EBEBRATT-Ed said:

Most states have no code for residential heating installations and if they do they seldom enforce it.

Virtually all mechanical codes have a clause that says equipment must be installed following manufacturer's instructions.

@mattmia2 I wish I could find this code and the clause "equipment must be installed following manufacturer's instructions." Do you know where I could find it?

EBEBRATT-Ed

@mattmia2
EBEBRATT-Ed said:
Most states have no code for residential heating installations and if they do they seldom enforce it.

of course every place has it but it's not enforced

Plumbers are trained in plumbing. Some learn heating and are excellent at it others not so much.

Most towns the plumbing & heating inspector is the same guy,

Most don't know headers or a hartford loop or have even herd of steam velocity.

As long as the gas piping is good, and it has a backflow preventer they are good to go

pecmsg

Code is Minimum Standard. 

Would an inspector know it was oversized, doubtful at best.