Seeking Guidance on Steam Boiler Issues (1928 Home with 1.95 Million BTU Weil-McLain)

shames

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

ScottSecor

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.

EBEBRATT-Ed

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.

Steamhead

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.

AdmiralYoda

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.

Jamie Hall

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.

DavidK_2

I'd hire an expert.

Mad Dog_2

That's a Commercial boiler. Get one if us Pros in there.…$$$ well spent. Mad Dog