Heater not working. Looking for help

Old 04-03-13, 06:16 PM
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Post Heater not working. Looking for help

I have a York diamond 80 furnace model # p4hua12n06401a which will not work. The panel flashes once which says "lockout caused by a flame sensed (1 sec on 1 sec off) when there should be no flame." Now I cleaned off my flame sensor with steel wool, tested the flame igniter, which works, tested the fan, which works, checked breakers, and still nothing. My last choice is to call a hvac company unless someone can help me.
Old 04-03-13, 06:48 PM
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Cycle the power off for 30 seconds to see if the error recures.

With the power off, check the resistance between the flame sensor and the furnace's ground. (check schematic to determine which pin corresponds to the flame sensor)

If it's anything other than infinity, there's a short to ground somewhere in the flame sensing circuit.

If it's infinity, the board is bad.

If you don't understand this post, it might be a good idea to call a hvac company.
Old 04-03-13, 06:59 PM
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Fan starts and flame sensor is grounded. Gas is going to water heater which is working.
Old 04-03-13, 08:03 PM
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Fan starts ? Which fan......the draft inducer on the flue ?

The flame sensor is mounted to the metal chassis or burner with a single screw. The rod itself is attached to the metal clip with ceramic. The rod is not grounded nor is it supposed to be.

Muggle wanted you to check from the actual flame sensor rod to ground with an ohmmeter.

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