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Site glass level?

VickiS Member Posts: 51
Is it normal for the level in the site glass to decrease over a couple of days time?  The attached picture is one that I took this morning. I set the water level to the correct level, at the marked black line, Thursday night.  So in a little over a day, the water level has decreased 2 inches below that mark.  The boiler is cold so all the condensate should be back in the boiler from the last cycle. 



  • Mark N
    Mark N Member Posts: 1,115

    No it is not normal. You have a leak or leaks. They need to be found and corrected. Check all of your vents and the packing nuts on the valves on the rads. Do you have wet returns? Are they buried? Hopefully your boiler hasn't developed a rot hole.
  • VickiS
    VickiS Member Posts: 51
    edited December 2012
    Re: Leak

    That's what I was afraid of. We have two wet returns and they are not buried. I don't see any evidence of them leaking. I've checked all the radiators and other than one vent that appears to not be working properly, I don't see anything that looks like a leak.  What's a rot hole?  Thanks.

  • ChrisJ
    ChrisJ Member Posts: 15,437
    packing nuts

    Keep in mind packing nuts on the radiator valves may leak and not be seen or heard.  If you have a float type LWCO the blowdown valve may leak and you won't even notice it, my last one was.  I found it by stuffing a papertowl up in it and checking it after a day or two, it was soaked.

    The boiler it self may be leaking, the only way to find out is to shut it down and let it cool completely then fill it to the top and check for leaks this includes the gauge glass it self.  And of course there is always a chance someone drilled a hole in one of your steam pipes in a crawl space to let the water out because its pitched wrong. Hey, it happened to me.
    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
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