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low heat

Tom_122 Member Posts: 3
I have hot water baseboard heat
The boiler shuts off before the desired temp.
It only keeps the house in the 60's
The gauge on the boiler usually reads between 5&10 psi
The water reads between 140 & 180 degrees
No matter what you set the thermostat at (or even jump the thermostat) it still shuts down.

would greatly appreciate any help


  • Big Ed_4
    Big Ed_4 Member Posts: 2,684

    This would matter most if its very cold outside ......Is most of your baseboard blocked? The air need to convect though the base board.Did you install plush carpet where there is no lower opening.

    Second thought . No water flow .Does your system used zone valves ? Either a bad end switch , relay or cirulator.
    I have enough experience to know , that I dont know it all
  • Tom_122
    Tom_122 Member Posts: 3

    no I don't think any are blocked no more than before it worked fine
    no water flow? I don't know
    It does have zoned valves

    bad end switch?
    relay or circulator?

    How do I check these?
    Maybe the circulation pump?
  • ChasMan
    ChasMan Member Posts: 462
    Low temps.

    The boiler will only come on if the internal water temperature is at the low setting of the aquastat and it will go off when it reaches the high point. These temperatures are set on your aquastat relay generaly so your observation of the temperature guage moving between 140 and 180 and the system shutting off even though the thermostat is not satisfied is normal. Id focus on your zone valves. Sounds like one of them is not opening. This should be easy to check. There is a manual operating lever. Make sure that they are opening. Checking the circulator is more difficult.
  • Tom_122
    Tom_122 Member Posts: 3
    low heat

    all the zoned valves are on.

    it does seem like a circulation problem

    no way to test pump?
    do you need to drain the expansion tank(ever)

  • ChasMan
    ChasMan Member Posts: 462

    If the zone valves are all on then it could be a circ issue. There is a little tool which is a magnet in a bubble that spins that can tell you if the pump motor is spinning. Might be easier to just replace the pump than test it lol.

    As for the expansion tank. It should be warm on top and cool on the bottom. If your tank fails It gets hot on top and warm / hot on the bottom. You would still have heat. Your pressure reads low but that could be your guage.

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