I've repaired natural gas appliances several times. Usually it is some sort of flame sensor and rather easy to replace. "The flame sensor is a rather simple d

I've repaired natural gas appliances several times. Usually it is some sort of flame sensor and rather easy to replace. "The flame sensor is a rather simple device located at the burner assembly. It's not much more than a thin, usually bent, metallic rod that sits in front of the flame stream inside the furnace. The purpose of the flame sensor is to confirm to the system that whenever the gas valve is open, a fire is actually present"