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cutter123 Member Posts: 1
I have a teckmar 252 two boiler control used for home heating and DHW. No error codes are showing, but the DHW is on along with the system and dominating the heat output such that the phaseIII water heater is overheating and the house is cold. I replaced the aquastat to the Phase III but the problem persists. Is this a Tekmar switch fault and can it be replaced or is a newTekmar necessary? Thanks


  • furnacefigher15
    furnacefigher15 Member Posts: 514
    It might be

    or it might be mis wired, or shorted.

    Try disconnecting the input demand for dhw at the tekmar. If it still displays that it is in dhw mode, I would think the tekmar is at fault.
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