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new steam boiler wont turn off at t stat

Carrier steam boiler has been working fine for 5 yrs. Suddenly since last week it keeps firing well past the thermostat setting. I changed out the batteries and checked the electrical connections at the boiler. No luck.

Could the sensor be bad?


  • escaseadjug1793177
    escaseadjug1793177 Member Posts: 22
    Steam Heat

    New (Burnham) gas steam boiler won't turn off at thermostat temp. Continues to run well past setting. Boilers piped according to manufactures instructions - forced hot water loop off bottom of boiler seems to work fine. Any ideas??
  • carol_3
    carol_3 Member Posts: 397

    My guess is that something other that the thermostat isn't wired to control the temp. What's wired to T-T on the boiler?
  • burnerman_2
    burnerman_2 Member Posts: 297
    what if

    what if u take a wire off t-t one time many moons ago i heard a story bout a bare wire inside the wall touchin causin the furnace to run past themostat setting just a thought royboy
  • heatguy
    heatguy Member Posts: 102

    sounds like they dont have a aquastat on baseboard loop and just tied into tt on boiler control need to put aquastat in series to turn boiler on and off
This discussion has been closed.