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thermostat for steam heat

mchema Member Posts: 37
I have a Hunter energy star thermostat it was here when me moved in. It has four setting for different times of the day. Generally I keep the house cooler at night verses the day. My problem is I notice the house gets really cold before the heat kicks on. I thought maybe it was just me but I have two other independent thermometers around the house (one is in the room with the thermostat). If the thermostat to control the boiler says it's 68 the other say it 66. Can there be something wrong with the thermostat that controls the boiler? When it does kick on and brings thermometers and thermostats up to the same temp temp.  What's with the 2 degree lag?  I read the hunter manual and can't figure out why this would be happening. The cycling is set to what I think is normal. Is it the wrong thermostat for the system. I did read in Dan's book it's best just to have a constant thermostat. 


  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,575
    choice of thermostat

    when you have both thermometers and the thermostat together [within 6 inches], do they all read the same temp?

    do you find that when the boiler fires, that the rads all have steam at the same time, for that is the desired result.

    most people here have had the best luck with the honeywell visionpro, which is a steam certified thermostat. your hunter may or may not be steam certified. dan's book  [available here] "the lost art of steam heating" goes into the subject of thermostat selection, and adjustment, in greater detail.--nbc
  • mchema
    mchema Member Posts: 37

    When I have thermometer next to the thermostat and the cycle has just ended (say I set the system to 68. Both will say 68 when the system reaches temp. Then it shuts off) But when the temp drops the thermometer will read 66 while the thermostat controlling the boiler reads 68. Sometimes there is even a 3 degree difference. 
  • JH_2
    JH_2 Member Posts: 57
    accuracy ?

    If they are next to each other and read different its probably just a difference in accuracy.

    That thermometer - is it digital, a liquid/mercury bulb type or one of those cheap bimetallic coil types (metal coil attached to a dial pointer)?.  If its the coil type stop worrying.  Those are not super accurate and a difference of a couple degrees wouldn't surprise me at all.
  • mchema
    mchema Member Posts: 37
    We have a couple

    around the house. We have two digital. The only reason I have them out is b/c I felt very cold for what the thermostat was reading. We had the digital thermometers in our old house and they read the same as the thermostat. Sooo I don't know... 
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