Furnace turns on for two minutes then shuts off
There are several reasons that your furnace would turn on and the quickly shut off before reaching the set thermostat temperature. There could be an issue with the flame sensor, limit switch, control board, pressure switch, draft inducer motor, flame rollout limit switch, or air flow problems. Perhaps the most common is the flame sensor. The flame sensor monitors the gas burner. If the flame sensor is unable to detect the flame, the control board will shut off voltage to the gas valve, ending the heat cycle. The flame sensor can become dirty or in some cases can crack. Many times the flame sensor can be cleaned with a pad and continue without issues. If the flame sensor has cracked, it will need to be replaced. Chances are if your furnace is short cycling you will need to call a certified technician.