The fan running has nothing to do with the ignition of the burner flame. It’s purpose is to blow cold air across the combustion chamber and out the opposite end of the heater with warm air. If the temperature switch doesn’t work it can be jumpered which allows the fan to run all the time. The only way to turn it off is to unplug the power cord. For the burner to ignite you need the proper fuel pressure, airshutter setting, and proper spark on the ignition electrodes. Also check to make sure your extension cord has the proper polarity. This can cause weird things to happen with the burner cycle. I’ve repaired hundreds of cords with reverse wires in the plug. Also use a 10, or 12 gauge extension cord for proper voltage supply.
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