Gas furnace blower will not kick on


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Old 01-10-13, 07:01 PM
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Gas furnace blower will not kick on

I have a Coleman D.E.S 80 gas furnace model #2845C666.

When the thermostat tells the furnace to blow heat, there is a fan that turns on (vent fan?), the ignitor glows, gas flows and flames start dancing and when the blower should turn on, it does not and the gas turns off but the fan (vent fan?) keeps going. I started having problems last winter.

I have turned off the furnace, turned off the gas and then turned them back on. Last winter, this worked. I would reset it and then it would start working. The furnace worked for a month or so but now, the blower will not turn on.

Any ideas? I have limited knowledge but from a logical standpoint, I seem to think the fan switch. I have attached the wiring diagram.

Thank you in advance for any help.
 
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Old 01-11-13, 04:33 PM
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cant read the photo you provided. I too would lean towards the fan switch. You can verify by checking for power to the blower motor.
 
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Old 01-11-13, 04:41 PM
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Thanks,

I have a better picture here: http://img546.imageshack.us/img546/1...acediagram.jpg

Where would be the best spot to place the multimeter leads to check for power to the blower. Would I be looking for 115 VAC? If there is power to the blower then, the fan switch is bad?

Thanks again.
 
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Old 01-11-13, 05:06 PM
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If you have 115 to the blower motor, it should run. That 115 comes thru the fan switch.
 
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Old 01-11-13, 05:38 PM
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Measure for 120VAC power at the 2 white arrows for heat mode, or 4 and the unmarked white arrow for cool mode.

If you have power, you might check the cap...

 
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Old 01-11-13, 06:06 PM
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That is awesome! Thank you so much. I will check the spots you showed me.
 
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Old 01-11-13, 06:19 PM
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Houston,
You're just too good with marking up wiring diagrams & such. Maybe one of these days this old geezer can learn to do such. Great job, thanks.
 
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Old 01-11-13, 06:28 PM
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Thanks.
I use Windows paint. I'd like to use Photoshop or something that used layers so I could remove the original image and only display the highlights.
 
 

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