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Glass tube filled - but boiler seems empty

frumpyjones Member Posts: 1
edited November 2018 in THE MAIN WALL
Hi all. I have a water boiler where the glass tube is totally filled. However, I think the boiler is close to empty. I replaced my low water cutoff myself last year, but I really don't want to bet my boiler that it works.

I have two valves on the boiler. Both are below the glass tube (and lower than the lowest valve on the tube). However, neither had any water coming out.

I turned off the boiler entirely and let it cool for about two hours. I then opened up the intake while leaving the one valve open, and then water did start to come out.

So, I think it's either filled just enough or not at all, but if the glass tube is my only way for knowing... What the heck do i do now?


  • kcopp
    kcopp Member Posts: 4,448
    They gauge glass tube valves can get mudded up...
    Pull out the handles and run a wire through and flush out any mud in the port.
    Then refill.

  • Gordo
    Gordo Member Posts: 857
    Is this the problem you're having?
    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
  • nicholas bonham-carter
    First of all, make sure the valves on the top and bottom of the sightglass are open. Of course they are open, when turned counter clockwise.
    As said, the tappings for the sightglass may be plugged up, and therefore not showing the true level in the boiler. Removing the glass tube, after turning those valves off would enable you to poke a flexible wire into the tapping all the way into the boiler section, dislodging any debris lodged in it.
    The probe for the LWCO may need to be cleaned, so as to be accurate in detecting the water level, and that may need professional intervention, although you could do it yourself.
    Learning how to do these various maintenance tasks will make you more independent of the need for the pro on the morning of January 1, when the temperature is very low, and the pros are very busy or sleeping in!—NBC