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Baseboard heat - house won't get above 60

TomM_12 Member Posts: 2
We have gas hot water heat with a Weil Mclain GV-4 boiler. Recently, the boiler quit in the middle of the night and the service tech indicated that the vent pipe was filled with debris and needed cleaned out. The boiler is now operating, however, the issue is that the house will not get above 60 degrees. The wall thermostat is calling for heat, yet the boiler comes on, runs for 5 minutes or so and then goes back to the Green light on the module like the boiler is waiting for a call for heat. I spoke with the service tech and he said that it could be the internal thermostat of the boiler which regulates the temperature based upon the return water coming back into the boiler. He said that I could remove the thermostat to temporarily see if this resolves the issue. Does this sound like a likely culprit? Is this something that can easily be done? I looked in the GV4 manual and I don't specifically see the internal thermostat listed, unless it is part of the "Bypass Circulator". The boiler is reading 180 degrees. The return line coming back in feels very lukewarm to the touch. Any suggestions/ideas are appreciated.


  • Eric_32
    Eric_32 Member Posts: 267
    Your boiler is running...

    and unless it is making hot water, then it IS responding from a call for heat or else it wouldn't be running.

    The " internal thermostat" is more commonly called a Hi-limit. Your boiler is now bouncing off Hi limit and not dumping it's heat off.

    Sounds like you have flow issues, bad circuilator or air in the zone.

    If the thermostat hasn't recently been messed with.... and it has good batteries (if it has them) then it's 98% not the issue.
  • TomM_12
    TomM_12 Member Posts: 2
    edited January 2014
    Thanks for reply

    Thanks Eric. No, the thermostat hasn't recently been messed with and the batteries are good. The thermostat indicates that it is calling for heat every minute of the day since the temp wont get to the desired setting.

    The circulator appears to be running. Could it be running but still be "bad"? I havent bled the system in a long time. Would air in the lines cause this big of an issue?

    By the way, this is a one zone setup (fairly small house, nothing too fancy).
  • Zman
    Zman Member Posts: 7,328
    edited January 2014

    As Eric stated, it sounds like a flow issue. Air could certainly be the problem. What is the system pressure? A picture of the boiler piping might help.

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • weil mclain

    Weil mclain boilers have very good air removal set up, if not used or installed correctly, you will have air bounded problems.. have any pictures??