3 flashes (due to blackout, then power back on)

[plumducky]

I have a furnace that won't start up since the power went out here for a few days, when IKE's residual winds came through here (Cincinnati, Ohio).

Is flashing three times and the flashes chart says Combustion Air Switch not closing.

No previous problems.

Coleman Model No: DGAA056BDTA
Serial Number: 040500210
Natural Gas

Does this furnace just need to be reset, somehow?

Thx much for any help.

[Robert]

Hi,

Check the 2 small tubes connected to booster motor and pressure switch for kinks, tears, blockages, looseness or water.


Make sure you have 24vac across 2 wires at pressure switch.


Make sure booster motor starts immediately and runs good and smooth.


Check flue air pipe from booster motor and up for straightness, damage, seperations, blockages.



Thanks,
Robert

[plumducky]

Thank you Robert...

When my thermostat calls for heat, I hear the booster motor trying to run (humming), but by comparison to a neighbor's identical configuration, mine doesn't make as much noise as his. I hear the same hum (on his) from the black cover (where the motor is) on the round, vertically positioned flue pipe (at right side of the box ), but on his, I hear more noise like the motor is driving the fan blades, right above the motor.

Can you tell me how old this furnace is, from the serial number, please?


Is it possible some debris can get into that pipe and drop down to jam the fan blades? This stopped working when our power went out for a few days, due to IKE's residual wind coming through here.

What I can't figure out is how to get the motor out of that flue pipe.

Am I on the right track?

[Robert]

Hi,

You're very welcome, happy to help. Yes, it is very possible.


Remove the 9 screws around the combustion air box behind gas valve that is attached to furnace facing.

Then move the air box, booster assembly and combustion air pipe down approx. 1" .

Remove air pipe then to allow removal of booster assembly.


Make sure it is all clean and undamaged and wheel is free spinning.



If so and the motor gets 120vac, it should run well enough to close pressure switch, if it doesn't, probably is bad.



Thanks,
Robert

[plumducky]

I'll give it a shot this weekend and post back here again soon as do...

Is this site & forum great or what!