Blower kicks on early and will only run 1 cycle. Have to turn down thermostat and turn it back up again to get furnace to come back on. It is gas.

  • What is the make and model of the furnace?
    – Tester101
    Apr 21, 2015 at 18:34
  • And what do you mean "blower kicks on early?"
    – feetwet
    May 16, 2015 at 2:29

1 Answer 1


The fact you have to turn it off or down to reset the unit tells us the unit is having a fault and locking out which requires a reset or a time span to pass before it will run again.

Typically this is due to the induced draft proving switch, it is a pressure switch that proves the induced draft motor is operating and it is ok to transition to ignition and burners.The switch has a tube that attaches to a barbed port on the induced draft housing.

This port will obstruct fully or partially and require reaming clear to allow sensing the inducer motors operation. The tubing can collect condensation if drooped and a low spot exists. The flame sensor also may be dirty, this requires 0000 steel wool to gently wipe it clean. The ignition module can also be going bad though less common to find than the aforementioned issues. If it were going off on a high limit it would require manually resetting the safety device tripped, as they will not auto reset.

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