Coleman Evcon mobile home furnace blower problems


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Old 03-28-17, 12:54 PM
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Coleman Evcon mobile home furnace blower problems

I have a Coleman/Evcon Presidential furnace Model #7970C856, serial # 099170150 in my mobile home.

It has had some issues in the past we replace the gas valve once, and the thermalcouple several times. Recently, Sunday, I switched the thermostat to 70, the burners came on and lit then the blower came on. Seemed to work fine 2 times. After that, the blower wouldn't come on.

Yesterday we tested again, the blower finally came on after about 10-15 minutes. I was thankful as it is getting chilly out.

This morning I thought I would time it. It took about 20 minutes for the blower to kick on after I set the thermostat. Then it ran for about a minute, shut off...after every 5 minutes passed the blower kick in.

Help, still not warm in New Mexico!
 
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Old 03-28-17, 02:05 PM
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Welcome to the forums.

It sounds like a problem with the blower motor. It could be as simple as a worn out capacitor to a tired motor.

Turn the power off and try to spin the blower by hand and see if it's binding or tight.
Check the actual motor after trying to start and see if it's real hot.
 
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Old 03-28-17, 02:57 PM
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Thanks I will try that when I get home.

Since I have lived there it has short cycled. Don't know if that helps.
 
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Old 03-28-17, 03:42 PM
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Some Colemans have a FAN ONLY setting where you could try it to see what the blower does.
If it short cycles on heat.... it could also be a fan thermostat that is inside the furnace and tells the blower when the furnace is hot enough for the blower to run.

These Coleman furnaces are not wired intuitively from the factory and are always rewired to work correctly. If you have A/C that is an additional wiring modification.
 
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Old 03-28-17, 03:53 PM
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No AC Unit to it...but we rewired a switch to the blower, don't ask me why, but the blower works fine, at least seems to.
 
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Old 03-28-17, 04:20 PM
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Then if you feel the blower itself is ok.... replace the fan thermostat.
The OEM part # is 7975-3281. It can be found at many places.

amazon/Coleman-Furnace-Replacement-Switch/dp/B00FGUPM52
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The part is #32 and its location is shown in the diagram. There should be two similar looking parts next to each other. It's the left thermostat.

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Old 03-29-17, 09:23 AM
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We called a pro sent him some pictures. I don't have one of those meters to check to see if the part is good but may have to get one. I will let you know.
 
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Old 03-29-17, 10:03 AM
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I do have another question.

If I get the replacement part of the fan switch should I also get the lower limit part at the same time? or just the fan switch?
 
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Old 04-01-17, 05:47 PM
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Fan switches on that furnace are notorious for going bad. I'd just replace the bad switch. Maybe even get a spare to keep on hand.
 
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Old 04-02-17, 04:38 PM
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I wouldn't even worry about checking it. Oder one and replace it. If it's not the problem you'll have a usable spare.
 
 

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