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built1950, Handyman
Category: Appliance
Satisfied Customers: 210
Experience:  Appliance Installer
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have model f80a woke up this morning and heater not working,

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have model f80a woke up this morning and heater not working, has 3 flashes (code) the manuel says air proving switch is open, whats that?

Thanks Pete
If the Air proving switch is open the combustion air blower should come on. It will run for a few seconds and close the air proving switch to allow the unit to start. If the air proving switch doesn't close (a safety mechanism) the unit will shut down. This does not necessarily mean the switch is bad. It may be doing its job telling you there is insufficient air flow. You may need a local tech to test . Last time I had this problem I took the blower off and found a dead squirrel blocking the duct.

God Bless
Customer: replied 7 years ago.



Neither of the blowers start at all, and both turn freely, there is a 5 second pause when I turn it on and off and then the LED flashes with the code. Is there a rest switch or something I can try ? The Air Proving switch is the the one with the vacume tube going into the furnace blower near the top of the unit right.




Yep. It senses the change in air pressure caused by the standing air becoming moving air so if the air doesn't move enough the switch won't close. As I explained before it could be a blocked duct. Beyond that you would test the combustion air motor. See if it's getting power, if so the motor or the start capacitor could be toast.

Edited by built1950 on 11/23/2009 at 6:06 PM EST
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Customer: replied 7 years ago.

Ok, I took off the exhaust from the flue, nothing in the duct and there is air flowing freely (suction up into the chimny) so I guess its and electrical problem (Motor or Capacitor), I will break down and call in a HVAC tech to look at it, thank for your time sir your answers were helpful, I'm a Truck Mechanic this thing does not have pistons so I should not mess with it anymore than I have,



Good luck