Steam venting from old vent on top of converted coal boiler

Brookhawk · January 28

Hello all.

Relatively new first-time homeowner — this is my fourth winter in the house. I appreciate any help or advice.

I have an original coal-era cast-iron steam boiler in a 1925 Brooklyn house, converted to natural gas. It’s a one-pipe steam system with a pressuretrol on a pigtail, sight glass, and manual water feed (no automatic feeder). The boiler still has the original coal-era vent/cap on top.

Current issue

Steam is coming out of the old vent on top of the boiler. I believe this may have happened in the past (possibly during very cold spells), but under more typical Brooklyn winter temperatures I haven’t really noticed it.

Here’s what I’m seeing

The steam sometimes sputters (steam with water droplets)
Steam from that vent only occurs while the boiler is firing
The steam stops completely when the burner shuts off
Some radiator air vents vent small amounts of steam when this is happening
Boiler water level in the sight glass remains stable
The boiler continues to heat the house
The issue is more noticeable during very cold weather with long run times

Questions

Anything I should be checking or doing immediately? What should I be looking at in the short term?

I do plan on updating the system, but that’s probably a separate discussion.

Pictures Below 👇

Thanks in advance.🙌

John B.

Grallert · January 28

It's likely that the old relief valve is finally failing. It's also likely that the leaky vents are are failing or gunked up. It's possible the boiler is making too much pressure which will compound the problems. Your pressure trol looks fine but I'd get the pigtail cleaned or replaced. From what you've posted I see nothing alarming.

Brookhawk · January 28

Thanks much🙏 I will have someone come and replace the valve and pigtail that and look things over. I am sure heating people are busy here in NYC right now..

ethicalpaul · January 28

Honestly I have no idea how that home could have changed hands with that system in place! Sure, the boiler has lasted and will last longer than any boiler built today but wow that thing is old

mattmia2 · January 28

look in the find a contractor at the top of this page, there are several good steam contractors in NYC.

EBEBRATT-Ed · January 29

New relief valve, clean/replace pigtail and check connection into boiler to make sure it is clear. Also set and adjust/clean pressure control to cut off the burner at 1.5psi.

Maybe a new pressure gauge as well.

mattmia2 · January 29

i bet that pressuretrol is old enough to have a mercury switch instead of the far inferior microswitch.

it could be over pressurizing and the relief valve is doing its job or it could be the relief valve failed.

like others said, check the pigtail is clear and maybe check the gauge and replace the ancient relief valve with a modern version piped to within 6" of the floor

mattmia2 · January 29

actually, first flood the boiler and make sure water doesn't come dripping out of the boiler itself. it could be the boiler has a hole in it and it is just coming out the jacket where there is a hole for the relief valve.

EBEBRATT-Ed · January 29

The PA404A never had a mercury switch. Not the original pressure control. The original would have had mercury. The safety valve is original as well as the pressure gauge.

But more important there is another safety control missing (or at least it is not in the pictures)

4GenPlumber · January 29

Not only do i not see a LWCO, where is all the near boiler piping, behind it?

leonz · January 29

That is an original Marsh instruments steam pressure gauge, if anything I would only replace it with another Marsh Instruments pressure gauge. The Marsh Instruments Company has always made high quality pressure gauges. It would be worth calling the company and asking if they would recalibrate and pressure test this gauge for you if you are concerned.

I have a Marsh instruments triple gauge for my coal stoker boiler and I sleep very well at night because I know I have a high quality pressure gauge. Your current pressure gauge could be used on the new boiler too if and when you replace that beautiful hand fed coal boiler.

Brookhawk · January 29

Thanks for all this info. I am 100% replacing this unit and reconfiguinging / renovating this whole room.

Updates - i had boiler safety check (2 years ago) and they did remove and clean the pigtail. I dont think there is a LWC. I never have seen the pressure gauge move, not sure if i should be seeing it move.. below are more pictures. I will be looking at all that was suggested to get me through till its replaced.. Thanks for the continued advice.. 🙌

4GenPlumber · January 29

Replacing that boiler is gonna cost you an arm and a leg. Not to scare you, but you are in Brooklyn I think you said? You are gonna need an asbestos abatement crew, probably a special permit for that in NYC. I know there is one for NJ. That is gonna need to be broke down and stripped in place.

AdmiralYoda · January 29

30psi gauges are required by code…they must read 2x the pressure relief valve rating (15psi). They are notorious for being very inaccurate at the low end of the readout. Best thing to do would be to install a Tee with two gauges…. a 0-30psi to make insurance happy, and a 0-3 or 0-5psi one so you can actually read what pressure you are operating at.

You can do all this work yourself, you only need a couple of wrenches.

For cleaning the pressuretrol:

Turn off the power to the boiler.
Remove the cover on the pressuretrol and disconnect the two wires and the conduit.
Remove the pressuretrol by screwing the entire assembly lefty-loosey :) from the nut on the bottom.
Run a large zip-tie or flexible pipe brush through the pigtail to clean it out.
Reassemble in reverse order with some Teflon tape added to the threads on the pigtail.

The pressure relief valve should also be replaced, they are a maintenance item.

Don't be in too much of a rush to replace this piece of history. A new one will heat the building the same way….but it will likely be much more efficient and have some fuel savings associated with it. But it will cost some big coin to start saving on fuel.

It may not be a bad idea to retrofit a LWCO to this beast for safety reasons if it is even possible. If a plug exists somewhere near or just below the bottom of the site glass it can be removed and a probe-type LWCO can be added.

AdmiralYoda · January 29

One more comment because I like old stuff. If you add up the radiation of all of your steam radiators (EDR) and compare them to the square feet of steam capacity of your boiler you can determine how well your boiler is sized.

If it is properly sized it shouldn't build much pressure under normal operating conditions. You could upgrade to a vaporstat instead of a pressuretrol which limits the pressure to a lower maximum than a pressuretrol.

Replace your radiator vents with some MoM's (Maid O' Mist) or Gortons and you can fine tune and balance your whole system. Add or upgrade your main pipe venting and you'll be operating at the full potential (and comfort) of this boiler.

You'll also significantly reduce your operating costs by wasting less fuel. You'll be more comfortable too.

You will have to do this stuff anyways when you get a new boiler….but this will help you squeeze every dollar out of your existing setup and help it live a stress free life until you dump some big $$$ on a new one!

4GenPlumber · January 30

Does it even have 24v for a probe LWCO? I assumed it was millivolt, can retrofit a 67G at the gauge cocks.

dabrakeman · January 30

I'd tune it up and milk that boiler until it dies. Could be a very long time.

EBEBRATT-Ed · January 31

Add a#67 LWCO, new safety valve and clean pigtail and pressure control

ethicalpaul · January 31

https://forum.heatinghelp.com/discussion/comment/1885389#Comment_1885389

You get all those plus Hartford Loop, Header, and Equalizer on a new boiler from this century!

EBEBRATT-Ed · January 31

@ethicalpaul

new boiler$$$$

Asbestos removal$$$$

Boiler install$$$$

Versus

LWCO $$$

Safety Valve$$

Pigtail$$

Labor$$$

ethicalpaul · January 31

True enough, but there's also a chance the old boiler will rust through any day now.

In which case you are looking at:

new boiler$$$$

Asbestos removal$$$$

Boiler install$$$$

PLUS

LWCO $$$

Safety Valve$$

Pigtail$$

Labor$$$

and let's not forget the longer it does last the longer you have:

Inefficiency$$ (per year)

dabrakeman · January 31

If he were able to save an $100/mo on his monthly heating bills I'd guesstimate it would probably take 25 years to pay back on a complete new boiler, asbestos removal and repiping. No way to know how soon the boiler would fail but these old boilers can tend to keep going a very long time. I'd add the lwco and relief valve, clean or replace the pigtail, test to make sure the pressuretrol is functioning properly, check to see if there is main venting present anywhere on the system and if not add and, replace the radiator vents that witness release of steam and don't close properly and repack or replace any inlet valves that leak. Much of this would have to be done with a new boiler from a system standpoint anyway.

EBEBRATT-Ed · January 31

@ethicalpaul

I would rather have the boiler he has then a brand new Burnham Independence

ethicalpaul · January 31

Full agreement!

pecmsg · January 31

converting a coil boiler to a gas wats the eff60, 65, 70% ?

When it’s time for resale all that asbestos and that antique will be lowering the value.

Steam venting from old vent on top of converted coal boiler

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