Seeking Guidance on Steam Boiler Issues (1928 Home with 1.95 Million BTU Weil-McLain)
Hello everyone,
I recently moved into a new-to-me home this July, though the house itself is far from new—it was built in 1928. It’s a large property, and part of its charm (and challenge) is its heating system: a 1.95 million BTU Weil-McLain LGB-16 steam boiler (16 sections total, 8 on each side).
I’ve been diving into the world of steam boilers, learning a lot in the process. While I genuinely enjoy gaining knowledge, I wish the circumstances were different, as my learning curve is being driven by what seem to be significant issues with the system. I’ve been reading We Got Steam Heat (a fantastic book, by the way), which has been a big help, but I still have so many questions. I’d be beyond grateful for any advice or guidance you could offer.
Here’s an overview of the situation and the issues I’m dealing with:
Leaks:
The prior owner assured me everything was working perfectly, mentioning that the boiler is only 10 years old. However, the HVAC company that has serviced the boiler for the past four years told me the system has been leaking water for at least that long. They provided notes from prior visits, indicating they repeatedly informed the previous owner, but the issue was ignored.
The main house appears to be losing 2–3 gallons of water per day with outside temperatures in the 50s and 60s (so the system isn’t running continuously).
The garage (a separate building with an apartment above it) is another story. When I turned on the garage heat, the system lost 12 gallons in a single day under similar weather conditions. There’s an air vent in the garage that pours out steam, though the HVAC company insists this isn’t the main source of the garage leak. Here's a video the air vent leaking: https://photos.app.goo.gl/1K16jU5fztcMfgUv5
Questions: What is a reasonable amount of water loss for a system of this size? Should I be concerned about these levels of water loss? Regarding the air vent in the garage, is it reasonable for me to try to replace that myself of should I have a professional do it?
Boiler Section Rust and Burner Issues:
The boiler appears to have a leak at the top of section 1 (photo below), but it’s not actively wet—just rusting. I haven’t seen or heard steam escaping from it.
Some burners near section 1 are also showing signs of rust (photo below), and one burner isn’t lighting at all. I suspect the valve might be clogged. The valve looks like it can be unscrewed, but I’m hesitant to try without guidance.
Questions:Could the rust on the boiler section and burners indicate a larger problem? Should I attempt to unclog the burner valve myself, or leave it to a professional?
Are the rusted sections something that needs to be addressed before we get deeper into the heating season, or can I wait? Would it fail suddenly and completely at some point or will I likely notice water leaking and have time to get it repaired then? The repair quote I received is quite high, and I understand it’s a labor-intensive job, but I’d like to know if it’s safe to hold off for now.
Condensate Pump Noise:
There’s a large condensate pump (photo below) that makes an awful noise when it runs. The motor itself doesn’t sound terrible, but there’s a loud banging noise after it stops. Based on We Got Steam Heat, this might be the check valve struggling to close.
Question: Is this noise normal for a system of this size, or should I investigate further?
Wet Returns and Sludge:
During weekly blowdowns, I see a lot of sludge. The HVAC company cleaned the burners and performed several tests, but they didn’t drain the wet returns or the boiler itself.
Question: Should I have the company come back to clean the wet returns and the boiler? Would this help with the sludge issue?
I’d be happy to provide photos or additional details if it helps clarify anything. Thank you in advance for your time and expertise—I greatly appreciate it!
PHOTOS / VIDEO
Boiler
Rust at top of boiler section 1
Rust under section 1
Rust on some of the burners (under section 1)
Condensate pump
Comments
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Your heating system is a little more complicated than what "we have steam heat" covers. I think you want a contractor that is focused on commercial steam heating systems, not a residential HVAC contractor.
Most if not all steam professionals prefer to not have zone valves on steam systems. In simple terms, the boiler and most of the piping is designed for one large zone. There are many issues with zoned steam systems that can be overcome but not easily.
Looking at the photo of the bottom of the boiler block, It appears to me that the there is a leak on the boiler at or near the end section. Could be a leaking lower elastomer ring (rubber gasket) or at least one of the cast iron sections has failed. Looking at the photo of the top of the boiler block, it looks like at least one section or another gasket is leaking. I would be very concerned, especially since this has been a long term leak. In many cases, we have "split" the boiler block hoping to simply clean the surface and replace the gasket(s), only to find a hairline crack or a deeply pitted mating surface.
Looking at the risers and the near boiler piping it appears the installer may not have followed Weil McLain's installation manual. Another photo or two from the the front of the boiler may clear this up.
With regard to the noises after the condensate pump turs off, this may be due to the check valve chattering. In most cases this can be fixed with modifying the piping and installing a spring check instead of a swing check. Oftentimes, we also intentionally slow the flow slightly as well. The pump and motor assembly appear to have been modified recently (as does the float switch). The motor appears to be an aftermarket replacement. The motor might not be the correct type for the pump.
There only appears to be one low water cutoff. In most cases, code requires two low water cutoffs, one must have manual reset. The code also requires a manual reset pressure control.
Lastly, I assume this is an enormous house. We service and have installed many LGB boilers in churches, schools, apartment houses, and very large homes. Most of these buildings have four through ten section LGB steam boilers. I am concerned that your boiler is grossly oversized and this may be contributing to some of your problems.
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Don't know where you are located but I would suggest "find a contractor" on this site and post your location. Someone may have a recommendation.
First thing to have done is find the leaks. This is mandatory. City water is loaded with fresh oxygen that will damage the boilers and the return piping and rot them out quickly.
If it had been leaking for 10 years that is a big issue.
I would also flush the returns and have the boilers skimmed. Replace any leaking air vents (steam lost is water lost)
That's just for starters.
Unfortunately if the systems have been leaking and adding MU water for a long time the boilers and return lines could be at the end of their life span.
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Part of the boiler issue is that they welded the header piping. LGBs with welded headers often leak like that, because the cast-iron boiler sections and the welded steel header expand differently. This can pull the sections apart so they leak.
Weil-McLain has specific instructions for this, but it seems to be too much bother for installers to actually read them.
All Steamed Up, Inc.
Towson, MD, USA
Steam, Vapor & Hot-Water Heating Specialists
Oil & Gas Burner Service
Consulting
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15 gallons per day and it isn't even cold is crazy excessive. 15 gallons a SEASON is excessive. Do you have any buried returns?
And have you added up all the EDR of your radiators? That would be step 1 in determining how oversized your boiler is.
And I agree with others…you need a steam expert that can handle commercial equipment. Your system is far from what is typical in most homes due to the size and complexity. Having the typical HVAC company work on this is like having a Lawn Mower Mechanic work on and diagnose an 18-wheeler's diesel engine. They might know enough to be dangerous but they aren't the right people for the job.
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Not much to add to the above comments. Please do tell us where this is located, so maybe we can help you find someone who actually does understand steam heat.
Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England2 -
I'd hire an expert.
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That's a Commercial boiler. Get one if us Pros in there.…$$$ well spent. Mad Dog
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I agree with all the above. That boiler may be on it's last lebs but befpre that the system should be carefully inspected for leaks. To make sure you understand now it should work you need more than "We Got Steam Heat", pick up a copy of
"The Lost Art of Steam Heat" (TLAOSH) and read it. You will then be able to understand what your being told and you will know if someone is blowing smoke up your ****.I suspect this work will be expensive but it will slowly be paid back with saved fuel and increased comfort. Start by making a table of all the radiators (L-W-H number of sections and number of columns per section) and convectors in the house; list the location, any radiator vents on them and any problems with that radiator. As you go along note any signs of moisture you find such as wood or plaster damage, rust, etc - this will let someone have a bullet list of possible problem areas. Check radiator valves carefully for signs leakage, many small leaks can add up.
Bob
Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
Vaporstat with a 12oz cut-out and 4oz cut-in
3PSI gauge1 -
You need a pro. Looks like new boiler time. Other thoughts:
- Unless you live in an enormous mansion, the current boiler is too big. Don't allow a replacement from anyone who didn't measure your radiators first.
- I second (or 3rd) that zones valves are a bad idea. They also necessitate the condensate tank, a relatively large expense. I would ditch the zone valves and the condensate tank, and convert back to the original gravity return.
New England SteamWorks
Service, Installation, & Restoration of Steam Heating Systems
newenglandsteamworks.com
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It’s clear that I need to bring in a professional who specializes in commercial steam systems, and I’m eager to take the next steps. I’ll be reaching out to find someone experienced to come and assess the system in person.
Since it sounds like there’s a considerable amount of work required to address the immediate issues (like finding and repairing leaks, replacing vents, and flushing the system) as well as longer-term work (potentially replacing the boiler or addressing the oversized system), I was wondering if it’s reasonable to request a daily rate from professionals. My thought is to pay for the time they spend working on the system rather than pricing each individual job. Is this something that’s common or practical in your experience?
For context, I’m located in Villanova, PA. If anyone has recommendations for local professionals or companies with expertise in commercial steam systems, I’d greatly appreciate it.
Thank you again for your advice—it’s been a tremendous help already!
Thank you for your detailed insights, especially regarding the boiler block and the potential issues with the welded headers. Here are more photos of the front of the boiler.
Yes, there are two lower water cutoffs, one on each site of the boiler. I was told to blow down the valve under each one once per week.
I will focus on finding a contractor with commercial steam expertise as you suggested. Your comments about the oversized boiler and the check valve modification are particularly helpful!
I appreciate your advice about the leaks and the critical importance of addressing them quickly to avoid further damage. I’ll prioritize finding those leaks and will have the returns flushed and the boiler skimmed. Thank you for explaining the long-term risks of adding make-up water—this really helped put things in perspective.
Your point about the welded header and its contribution to leaks was very illuminating. It seems like there’s a lot of work ahead, but knowing the root cause helps. I’ll make sure that any future repairs or replacements follow Weil-McLain’s instructions. Thank you for sharing your expertise!
Thank you for highlighting the excessive water loss—it was shocking to hear that 15 gallons per season is considered excessive, let alone per day! I’ll also focus on finding a steam expert for this system instead of relying on a general HVAC contractor. Your analogy of the lawnmower mechanic was spot on and really drove the point home.
Thanks for your reply, and I appreciate the offer to help find someone knowledgeable about steam systems. I’m in Villanova, PA, and would be grateful for any recommendations if you know professionals in the area.
Your suggestion to create a detailed radiator inventory is fantastic—thank you! I’ll start compiling that information and noting any visible signs of leaks or damage.
Thank you for your practical advice about boiler sizing and avoiding zone valves. If a replacement becomes necessary, I’ll make sure the radiators are measured and will discuss the possibility of eliminating the condensate tank and returning to a gravity system. Your experience is much appreciated!
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Contact the Hurst Boiler company to find their representative in your area. They can install a new steam boiler for your heating needs.
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Villanova? Just moved my son out to an apartment in Conshohocken a few weeks ago.
It seems houses of that 1928 era in that area used radiator enclosures extensively. Depending upon the exact configuration of those enclosures the effective amount of steam that can be condensed by the radiator can be decreased or increased due to changes in the convective airflow. While most of us can go around our homes in less than an hour to total up all our sqft of EDR for boiler sizing purposes yours might take a tad longer:)
Pages 7 and 8 of Dan Holohans "Every Darn Radiator" goes through the impact of various configurations of enclosures on radiator output/EDR. This would be worth considering when sizing up your connected load vs boiler sizing. I'm not comfortable sending out his copyrighted text directly but the book can be obtained either on Amazon or better from the store on this site. Good reference for you or whoever you will have working with your system. Please keep us posted and continue to ask questions as they come up.
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Hello,
I have a 10 year old Weil-McLain steam boiler with 16 sections, and I've discovered a leak between sections 1 and 2. I'm new to the home so I don't know how long it's been leaking. Also, I haven't noticed any visible wet spots, but there are signs of rust between the first two sections. The boiler has a water meter attached, and it's clear that it’s taking in a few gallons of fresh water daily, however, this may be from the boiler leaking and/or from other leaks in the system.
I've consulted a few professionals, and they all recommend replacing the first section or possibly the first two sections of the boiler or potentially replacing the whole boiler. However, even just the repair comes at a very significant dollar cost. Adding to my concern, it seems the header over the boiler may not be configured correctly, which might have caused the leaks in the first place. If that’s the case, replacing the sections may not prevent the problem from recurring.
I see three potential options here and would appreciate your thoughts on the logic behind them:
- Replace the First One or Two Sections
While this might stop the immediate leak, I'm concerned that it could be a temporary fix, especially if the header configuration isn’t addressed. - Replace the Entire Boiler and Redo the Header
This seems like the most comprehensive solution, but it’s also the most expensive. It would address both the leak and the potential root cause (header configuration), but I'm unsure if it's necessary to go this route immediately. - Do Nothing for Now Let the boiler continue to take on fresh water despite the risks of further corrosion. This might buy me a few more years before having to replace the boiler entirely. Right now, the boiler is heating the house effectively, and there are no apparent safety issues. I know this approach could accelerate the boiler’s decline but if I'm going to end up replacing the whole boiler eventually, I feel like I might as well get as much use as possible out of the current one before committing to that expense.
I'm leaning towards Option 3 to maximize the boiler's remaining life and defer the costs of replacement. Does this logic make sense, or am I risking bigger problems down the road? Has anyone dealt with a similar situation, and if so, what approach did you take? Any advice or insights would be greatly appreciated.
Thank you in advance for your help!
0 - Replace the First One or Two Sections
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You might be able to extend the life of the boiler and give yourself some thinking time by adding sodium silicate to the water. Or any "Boiler Weld" product. Usually frowned Upon but often a good solution. It's not that uncommon for those to develop leaks in the end sections and those are the easiest to replace. That's what I would suggest. The welded headers are the cause of these types of leaks I think.
Miss Hall's School service mechanic, greenhouse manager, teacher, dog walker and designated driver
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[Not a professional]
Several gallons a day is a lot of water. With that will come a lot of fresh oxygen every day, which will accelerate corrosion. What do the pros think — can this setup get through one more winter?This thing is absolutely massive — 16 sections? that's huge. Per the WM website, that's two EG-75 boilers sandwiched together, with an input of 564 MBTU/hour.
See https://www.weil-mclain.com/products/eg-series-6-gas-boilerYou say you are "new to the home" so I'm assuming it's a residence. I see the separate steam supply for the "garage" so that indicates a certain expanse; maybe a main house and two outbuildings? It would be worth your while to do the following:
#1 Determine the installed EDR, a measure of the sum total of the radiators being served by this boiler, and
#2 Learn over your first winter whether you need all that radiation.So running as-is for a few months, if feasible, could pay some dividends.
A lot of us have downsized significantly from the radiators installed a hundred years ago. This is due to increased insulation, or because only part of the house is fully heated, and also we no longer sleep with the windows open year-round.
Whatever radiators are actually in use will then determine how much boiler you need.
This ought to be an interesting thread.
cheers -m0 -
I just saw your other thread, which has more information and better pictures.
It may be a good idea to merge the two, or close this one. -m
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@shames, we've merged your discussions into one here to minimize confusion. Thanks.
Forum Moderator
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That welded header designed the way it is will pull the sections of the boiler apart and make it leak.
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I found Hercules Boiler Liquid at Supply House and might give that a try. Thanks for the recommendation and for providing you opinion of the welded headers.
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Yes, it's a large home but also might still have an over-sized boiler. I agree, if I can get through one winter then I'll understand a lot more about what is working and what isn't working with the current system.
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I considered after I submitted the first post that maybe I tried to put to much into one post (e.g., too many questions) which is why I started a separate thread with a single focus. That said, thanks for merging them, it makes sense.
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Could the header be replaced while reusing the boiler (assuming the current leaks are fixed)? Would that be an economical?
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There are many possibilities. There's also a lot of money in play — feeding two million BTU/hour is not chump change. If you're in this house long-term, it behooves you to get it right. It's already been said: there is an excellent chance your existing boiler is far too big.
The parameter space here is large. You have two huge sandwiched boilers, put together (and probably also pulled apart) by poorly constructed near-boiler piping.
You also have several heating zones. A good argument could be made for separating the whole enterprise into two or even three separate installations. Surely the "garage" has different needs than the house, but there could be an entire apartment above it, so maybe it's just a house…there's too much we don't know to be able to point you one way or the other.
I find this fascinating and would like more pictures and more details, but I think the best advice you've already gotten: Find a professional. These boilers may be fixable or they may be too far gone from all the fresh-water corrosion. Someone with experience could tell you.
But no matter what you do: please tell us how the story ends. I've got it bookmarked for a reason. Cool stuff.
https://www.heatinghelp.com/find-a-contractor/1 -
It may make sense if your boiler is:
A. Properly sized for the radiation
B. In good shape.
Usually it's better to start fresh.
Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.0
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