Tempstar Furnace Troubleshooting Flow Chart

Is your furnace... The problem might be your... What's wrong? How you can fix it:
Not heating? Circuit Breaker/Fuse Your furnace’s fuse has blown, or the circuit breaker has shorted. Either reset the furnace’s circuit breaker or replace the blown switch completely.
Igniter Either the igniter is defective or cracked. Check to see if the igniter is cracked and replace it If it’s not, test it with a multimeter to see if it’s defective.
Cycling irregularly? Thermostat Your thermostat is likely not adjusting correctly. Use your thermostat’s adjustable calibration scale to adjust the heat anticipator. If this doesn’t work or isn’t an option, replace the thermostat.
Not blowing hot air? Blower Motor Your furnace’s blower mower may be completely burnt out, or the connecting belt may have snapped. If the blower motor is receiving power but isn’t running, replace the motor. However, if it does run, it’s more likely that the connecting belt has snapped, replace it.
Blowing too much air? Control Board The relay on the control board that regulates how much voltage is sent to the blower motor has failed. You will have to replace the control board.
Thermostat The thermostat contact that controls the blower motor function might be stuck in a closed position. You’ll have to use a multimeter to check for continuity if this appears to be the issue then replace the thermostat.
Starting and then stopping shortly after? Flame Sensor The flame sensor may not be able to sense the presence of a flame due to it being dirty or defective. If the flame sensor is dirty, use an abrasive pad to wipe it clean. If it’s defective, replace the flame sensor.