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Low Water Cut Off stops burner

STvex Member Posts: 71
My low water cut off keeps stopping the burner even though it seems like there is no low water. It never calls for more water just kicks the burner back on after one or two minutes. The red light comes on, it stops the burner, then two minutes later, the red goes off and burner comes back on. Does this a lot. Is there a reason why? Help is very much appreciated. Have weil mclain steam boiler, pipes insulated, pressure gauge at 2 but rarely do i see the needle pick up, let alone come close to the 2 reading.


  • Jamie Hall
    Jamie Hall Member Posts: 21,524
    Slow condensate return for some reason? Worth checking for. Be happy that you have the sort of LWCO that doesn't immediately get annoyed and add water...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Fred
    Fred Member Posts: 8,541
    Is there much bounce in the water in the site glass? More than 1/2 to 3/4 inch? It may need a skim. When was the last time the LWCO probe was cleaned or replaced? Does it have teflon tape on it? They don't ground very well with tape. Just use a little pipe dope.
  • STvex
    STvex Member Posts: 71
    Its a new LWCO. There is a little bounce and there is blue teflon tape. I will take the teflon tape out and put pipe dope. If it still bounces, would it be a problem turning the burner off? I'd rather wait until the spring to skim since i have a old boiler and don't want to mess with it in the start of winter.
  • STvex
    STvex Member Posts: 71
    This also happens at the beginning after the boiler has been off for a while, would slow return still be a problem and how do i look for this?
  • Fred
    Fred Member Posts: 8,541
    Taking the tape off isn't going to fix the bounce. It will just help ground that probe. A little bounce 1/2 to 3/4 inch is normal. If much more than that, skimming is the likely fix.
  • kcopp
    kcopp Member Posts: 4,257
    I would skim it more. Is there a low water check light on the control? Hydrolevel calls it a cycle-gard....its a bit of a pain. Every so often it will check the level to double check its function.
  • ChrisJ
    ChrisJ Member Posts: 14,946
    Can you post pictures of the piping around the boiler?

    What happens to the water level in the gauge glass when this happens, does it drop, or go up or neither?

    Skimming is nothing to be afraid of and should post no risk assuming you have the skim port already set up for it. All you're doing is removing water and adding some.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment