Leaky steam boiler replacement advice

steamoptions · January 2020

Hi Folks,

I am looking for advice on replacing my defective Burnam IN6 boiler. The boiler was installed in 2015. I bought the house 3 years ago - so since I am not the original owner - no warranty! The leak is on the top of the end section in the back under the flue. In retrospect, the boiler was probably leaking already last year - it was already using more than 2 gallons a month, so it probably failed within 4 years of installation.

I've had a few heating contractors in to bid on repair or replacement, and heard various theories about why it failed so fast. One is that it is oversized. Radiator sq ft. is 340, IN6 makes 450. It does short cycle, even with the leak. The other theory is there should have be two risers. One of the contractors looked up the history an said that this unit had already been replaced under warranty. I've attached pictures of the leak.

I am trying to figure out the right replacement. One contractor proposed an IN5, leaving the existing piping pretty much as is. The other would reconfigure the piping, but he also didn't know what a Vaporstat was and claimed it would void (my already void) warranty, so I wasn't filled with confidence. He provided three options, IN6, WellMclain EG-50, and Slantfin GXHA-160. The IN5 and Slantfin are roughly the same cost, the other options are substantially higher.

Repair was also an option, at roughly 2/3rd the cost. My concern here is the damage 100+ gallons of water over the last five years might have done to the other sections.

So - IN5 might be a bit too small if I add the additional radiators? Should the IN5/6 have two risers? Should I even consider Burnam given the apparent poor quality of of this unit - or is this obviously because of a poor install and/or bad sizing?

Here are some other things to consider:

town water
other than short cycling, I have no issues with heat distribution, it seems pretty even
there is a hot water loop that feeds about 40ft of baseboard as backup for a minisplit, the system tends to short cycle when this is running (dilution is adjusted to maintain about 180F)
there are two radiators missing out of 12, and both will probably be replaced at some point, bringing sq. ft to about 400
mains are insulated, there are two branches, one 20ft and one 18ft, only the 18ft has a main valve

Jamie Hall · January 2020

Step 1.. Match the boiler's EDR rating as closely as you can to the installed radiation. If you must err, a slightly smaller EDR than the radiation is better than larger. Some, but not all, boilers can be fired to a range of radiation demands.

Step 2. Select an installer who is familiar with the boiler to be installed and knows and understands steam heat and does a quality job (your person who didn't know what a pressuretrol was would not be a good choice!). An installer who knows what he or she is doing is much more important than the brand of boiler (all of the ones you mention are good).

Step 3. Make sure that the boiler is installed correctly. The manufacturer will provide a piping diagram -- which is the absolute minimum that should be even considered.

The hot water loop is not a factor in sizing.

The lack of a main vent on one main must be corrected -- and I wouldn't be surprised if the other one was too small.

newagedawn · January 2020

agree with jamie, and DO NOT GET ANOTHER BURNHAM. peerless makes an awesome steam boiler, i have installed many over the yrs and have had NO problems

ethicalpaul · January 2020

What made it fail though? Was it rotted from within or from the combustion side?

BobC · January 2020

Early boiler failure would make me take a close look at the water quality in your area.

Is this house on town water or is the house on it's own well? Some area's have high chlorides in the water supply and that will kill a cast iron boiler - some area's between Boston and Providence are known to have high chlorides.

Bob

B_Sloane · January 2020

Peerless, or WM
Smith as a third choice

pecmsg · January 2020

How old is this house?

If more then 30 years what improvements have been made to tighten the envelope?

steamoptions · January 2020

ethicalpaul said:
What made it fail though? Was it rotted from within or from the combustion side?

To my eye it rotted from the inside out, but that is a guess based on the fact the rest of the exterior is rot free. The interior photo is through the safety valve/skimming tap.

steamoptions · January 2020

BobC said:
Early boiler failure would make me take a close look at the water quality in your area.

Is this house on town water or is the house on it's own well? Some area's have high chlorides in the water supply and that will kill a cast iron boiler - some area's between Boston and Providence are known to have high chlorides.

Bob

House is on town water. I'm trying to track down a water analysis. But how likely is that to have affected a spot above the water line?

steamoptions · January 2020

pecmsg said:
How old is this house?

If more then 30 years what improvements have been made to tighten the envelope?

House is circa 1890. Not sure when they switched from stoves to steam but it was definitely more than 30 years ago. House as some blown in cellulose but I only see half-harted attempts to improve the envelope. But my understanding is I need to size the boiler to the radiators irrespective of how leaky the house is, correct?

steamoptions · January 2020

Jamie Hall said:
Step 1.. Match the boiler's EDR rating as closely as you can to the installed radiation. If you must err, a slightly smaller EDR than the radiation is better than larger. Some, but not all, boilers can be fired to a range of radiation demands.

How much smaller would you consider slightly smaller in terms of sq ft steam? Would, say 50sq ft undersized be too small?

Jamie Hall · January 2020

It's a percentage, not an amount. I'd not go more than 10% under if I could help it.

And yes, the boiler is sized to the radiation, not the house heat loss.

Which is not to say you shouldn't consider tightening up the envelope. Insulation, good storm windows (there are some neat ones from Innerglass in Simsbury, CT which work wonders -- much better than the replacement windows you see advertised), draught sealing... it all helps.

clammy · January 2020

Where are u located ,I know in my area water is terrible high in tds which is not the best for any boiler weather steam or hot water . On your next boiler have a califee demileralizing filter a very good investment but few and far between will have a clue . I see you have a hot water loop off the bottom of your boiler personally not the biggest fan but it is what it is I would think it should be isolated and pressure tested if not all the pipe is visible . On another note have your radiator valves and venting been checked for leaks ? From your photo it looks like all piping is visible so I would think no buried returns or wet returns ? If there are no main vents on ur dry returns when boiler replaced tee s should be installed and main vents added. One last note that header looks on the small side and both boiler tapping should be used I would also say that on the boiler return there should be full sized tees soone can drain and wand out any mud which will build up in the bottom on the boiler it’s only common sense and is done on every boiler I install if it ain’t there ur not gonna get the bottom of the boiler clean nor will be able to wand the boiler out every few years to ensure that your not handing heat transfer due to liquid mud settling in the bottom of your boiler . I m not a fan of Burmham at all and usually install peerless but it depends upon access and space but as all will say it s not the boiler but the near boiler piping and header which really determines how well your system will perform and when replacing a steam boiler there’s a lot more then just the boiler and near boiler piping it’s making sure the system mains are vented properly and that the radiators are properly vented and that all radiator supply valves are not leaking Peace and good luck clammy

ethicalpaul · January 2020

No one can pack more good advice into a single paragraph than @clammy can. I owe you a drink or lunch or something

pecmsg · January 2020

Jamie Hall said:
It's a percentage, not an amount. I'd not go more than 10% under if I could help it.

And yes, the boiler is sized to the radiation, not the house heat loss.

Which is not to say you shouldn't consider tightening up the envelope. Insulation, good storm windows (there are some neat ones from Innerglass in Simsbury, CT which work wonders -- much better than the replacement windows you see advertised), draught sealing... it all helps.

Jamie

The reason I ask is if that envelope has been tightened then the total EDR is too high also. That radiator was designed for a room with no insulation, vapor barrier, leaky windows. Now tighten that room and the existing radiator is too large.

Jamie Hall · January 2020

pecmsg said:

Jamie Hall said:
It's a percentage, not an amount. I'd not go more than 10% under if I could help it.

And yes, the boiler is sized to the radiation, not the house heat loss.

Which is not to say you shouldn't consider tightening up the envelope. Insulation, good storm windows (there are some neat ones from Innerglass in Simsbury, CT which work wonders -- much better than the replacement windows you see advertised), draught sealing... it all helps.
Jamie

The reason I ask is if that envelope has been tightened then the total EDR is too high also. That radiator was designed for a room with no insulation, vapor barrier, leaky windows. Now tighten that room and the existing radiator is too large.

That is very often the case. It doesn't matter. The boiler is still sized to the radiation. That said, if you want to downsize the radiation -- install a new radiator in place of the existing one -- you can do that. Otherwise... just run the boiler less often, or for a shorter time, no?

ChrisJ · January 2020

More and more I'm glad I don't have a blue boiler in my basement. I think I made the right decision back in 2011.

That said, I agree with @Jamie Hall on sizing.

Mark N · January 2020

@steamoptions all leaks have to located and fixed. Excessive feed water will cause any steam boiler to fail. Check all the vents. Tighten all the packing nuts and the union on the radiator valves. Water usage should only be 2 or 3 gallons a year.

mikeg2015 · January 2020

MFG’s should ship their boiler with a Cross for the return. That’s the one mistake I made installing my boiler. With a cross you can flush it, wand it, inspect it, and a cross and a plug is like $15 more than just a tee.

You probably need some sort of boiler treatment and need to find all stem leaks in the house. The oversized boiler will cycle on pressure in many cases.

I know I have some leaks at 1psi, where as at 1oz of pressure I have none I can find. So smaller boiler should reduce water use. The EDR output includes pickup factor. I think 33% is pretty excessive unless it’s a uninsulated header in a cold basement or risers in outside walls.

I’m still waiting for the story where there was a undersized boiler and no amount of reducing venting rate or throttling steam valves (2 pipe) could resolve.

Jamie Hall · January 2020

You'll wait a long time for that story, @mikeg2015 !

But on leaks. It is absolutely astonishing how much water can be lost through what looks like an inconsequential little drip. A tiny drip -- say 5 ml every second -- adds up to a gallon a day, and you may never notice it unless you are really looking. So look. Hard.

Hap_Hazzard · January 2020

steamoptions said:
House is on town water. I'm trying to track down a water analysis. But how likely is that to have affected a spot above the water line?

Not that likely, but if your next boiler fails below the water line you won't be too happy. Pool and spa shops can do basic water tests (pH, hardness, alkalinity and certain metals, but usually not TDS) no charge, and they're not too busy this time of year.

Leaky steam boiler replacement advice

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