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sight glass problem

ghs Member Posts: 2
HI. New here. I have a gas fired Utica steam boiler in my home. When draining dirty water out of the furnace, the sight glass stays full but the low water warning light comes on and the auto fill adds water. This has not happened before when the level in the sight glass does not drop when draining water. Any ideas what is going on?


  • kcopp
    kcopp Member Posts: 4,188
    sounds like....

    the bottom drain cock on the sight glass is in the shut position. Make sure it is all the way open and not clogged.
  • ghs
    ghs Member Posts: 2
    sight glass

    Thank you for the reply. Yes, the bottom valve is closed as is the top valve of the sight glass. I do not touch these so I do not know if that is the way they should be. I will open it and see if some of the water drains out. If not then it appears it may be clogged, correct? The furnace runs just fine other wise but I cannot see the proper water level.
  • kcopp
    kcopp Member Posts: 4,188
    thats the problem...

    the valves don't drain they allow water to enter and leave the glass. If they are closed you won't have the flow. Open them up fully... kpc
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