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Boiler is empty -- cause unknown

***one-pipe steam***

So we turned on our steam a couple weeks ago.  Suddenly today it stopped working. I went downstairs into the pre- Victorian dungeon basement: 

-boiler was empty--no water in it and no evidence of leaks around it
-pilot was working and lit
-LWCO(float type) was not working last year and hadn't gotten around to fixing it yet so it could be broken
-auto water feeder works for manual fill,  doesn't switch on when I empty boiler

Momentarily setting aside the nagging issue of what caused the boiler to empty in the first place, tried getting it back online.  Assuming it was the LWCO that shut off, I checked that boiler was cold, filled it manually, turned off/on the main boiler switch, called for heat....----but gas valve still did not turn on.  Assuming the LWCO shut off boiler,   is there something I need to reset the cut-off switch on it?

I haven't checked any of the other safeties/circuit components but will try to narrow down the culprit by jumping safeties and/or checking switches for continuity.

Back to nagging issue--the cause of the empty boiler.  My initial thoughts are caused by a combination:

--1)bad auto feeder
 2) over last two weeks,  water level was steadily diminished by steam getting through some spitting rad or main vents(new Gordon #2 main vent spits a bit), or bad partially closed rad valves causing.  I checked with my neighbors about any evidence of leaks and haven't heard back.  As for my apartment, we have a large living room rad that sounds like it is filled with water during a heating cycle--you can hear it sloshing.  It has needed proper pitching for years and has sounded like that but I put it off.  My wife suspects water is sitting in the radiator and suggested we correct the pitch and let it return thru return piping.  Is it possible this is where the boiler water went?  

I shut off the boiler and am calling a local steam expert.
We have good specialists in the area but thought I'd ask the experts on here while I wait in case of delays. 


  • George76
    George76 Member Posts: 27
    I just wanted to clarify a couple things:
    -"water level was steadily diminished by steam getting through some spitting rad or main vents"  <---this is a theory, not what actually happened...
    --yes, I know restarting a leaky boiler without an operating LWCO would be very dangerous---i just wanted to see whether the cut-off and water feed were working 
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,852
    edited October 2020
    Some float type LWCO may use the same float to operate the water feed and the safety burner shut off. So if the LWCO does not shut off the burner when the water is low, that same float that does not know the water is low to shut off the burner also does not know to add water because the water is low. Not knowing the water is low means it can't do any low water function it is designed to do. Fix, clean, or replace the LWCO unless you have a few extra thousand $$$ for a new boiler.

    Some commercial boiler controls have a manual reset for high pressure or low water. If someone added a manual reset to your boiler that means the regular operating control has failed and the manual reset control had to step up to protect the boiler. A Pro is definitely recommended here

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • motoguy128
    motoguy128 Member Posts: 393
    Is it empty or just below the sight glass? If its Completely empty and there are no evidence of leaks. The water boiled off and the metal was crazy hot and I’d be surprised if there isn’t damage of some sort.

    Sounds like you need a pro.

    I just worked on a system that was venting a LOT of water and leaking at some unions, pitch issues, hammering. Just replaced a 2’ section of pipe and there is PITTING.... a lot of pitting and this was pipe that’s only 15 years old I’d estimate... and we have very good water quality. Even cheap DHW heaters last 30+ years.. Get the leaks or bad vents fixed or you will kill the while thing.

    I’d guess to start your pressure is set too high and the vents are leaking when it gets above 1 or 2 psi.... and wet steam and getting thrown into the vents. Might not have enough main vents.
  • dopey27177
    dopey27177 Member Posts: 887
    Can not offer advice because
    1. you indicate a low water cutoff problem that needed fixing last year.
    2. improperly pitched radiators.
    3. 3. Spitting vent valves.
    4. . An automatic water feeder that does not work.

    When you get those items repaired come back to this site and I will be able to assist you with correcting problems if there are any after the repair.