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Combustion Air Switch Failed to Close

Posted: Thu Nov 04, 2010 3:43 pm
by freddy6282
I have a furnace model DGAT056BDF that worked fine last winter but when i tried to turn it on for the first time this year, it wouldn't start and showed 3 flashing lights for the error code, which on my furnace reads "Combustion air switch failed to close" I couldn't hear the pressure switch clicking or sealing off when it was on, yet was getting voltage to the terminals, so i tried replacing the pressure switch with no success. What parts should i be looking at, or what else could be causing the error code to come up? Any help would be greatly appreciated!

Thank You!
Freddy

Re: Combustion Air Switch Failed to Close

Posted: Fri Nov 05, 2010 10:51 pm
by Robert
Blockage or leak in combustion air pipe, combustion motor or wheel faulty-dirty, tubes to pressure kinked, loose or clogged.

IF all ok, 24vac to one of the two wires at switch and a new switch installed, time to call an hvac tech.


Thanks,
Robert

Re: Combustion Air Switch Failed to Close

Posted: Sat Nov 06, 2010 3:44 am
by freddy6282
Thanks I'll check to make sure the motor and wheel aren't dirty, tubes look to be fine. Appreciate the help!

Re: Combustion Air Switch Failed to Close

Posted: Sat Nov 06, 2010 12:38 pm
by freddy6282
For anyone else who might be having the same problem as I had...It was indeed the fan on the combustion blower, it was seized up and needed to be cleaned and lubricated.

Re: Combustion Air Switch Failed to Close

Posted: Sun Nov 07, 2010 1:13 am
by Robert
Hi,

You're very welcome, happy to help. Glad it is taken care of.


Thanks,
Robert