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Honeywell Thermostat: CT87K

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in THE MAIN WALL
The CT87 is a retail thermostat. Do you have hot water(hydronic) or steam heat? On the back of the thermostat, you should have set the small dip switches to match the system you have. Out of the box, they are set for forced air. If the setting is correct, and you still have the problem, take it back for a refund. There is no internal setting.

Comments

  • RobLC
    RobLC Member Posts: 93
    Honeywell Thermostat: CT87K: Round NonProgrammable

    Just purchased a Honeywell CT87K Round NonProgrammable thermostat for heat only.

    I only have two thermostat wires, a white and a black. There are also two clock wires which I'm not using with the round thermostat because there's no clock.

    The thermostat works but not quite right. It will only turn the boiler on if you set the thermostat at 75 degrees.
    Even if the thermometer is 10 degrees lower. It turns on at 75 degrees and turns off at 74 degrees.

    If I put the thermostat at 68 or 70 degrees, it won't turn on. I have to put it to 75 before it turns on.

    Do any of the professionals have any idea why this is happening?

    Is the thermostat defective?

    Or is there some kind of internal setpoint in this unit?

    Any help would be appreciated.

    Thank you.

    Robert
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