I have a Thermo Pride forced air oil heating unit in my home and recently the blower motor has been acting up. Sometimes the blower motor fails to start when the furnace starts. It just makes a buzzing noise and after sometime will get hot to the touch.
So i decided to take the motor apart and clean it with an air compressor. When i sprayed the compressed air into the motor a considerable amount of a reddish colored dust came out. Any idea what that may be? Also i took the start up switch out and noticed the copper contacts had soot on them and pitting was evident, which lead me to believe there was arching. I cleaned the switch with rubbing alcohol and slightly sanded the pitting with a real fine grit emory board. The copper cleaned up nicely with very minimal sanding. I thought for sure i had found the problem.
Well, after about 5 days or so the motor was back to its funk, buzzing on start up and hot.
Here's the kicker... after letting the motor cool it will usually start again...upon doing so, if i turn the thermostat from "auto fan" to "always on" the motor does not have any problems and is cool to the touch. I've been running it a week on the "always on" selection and the fan has no problems. When i turn the thermostat to "auto fan" after a couple of days of successfully cycling on and off that is when the motor returns to its funk.
Any suggestions or ideas as to what the problem might be? I would like to fix the motor if at all possible. I would hate to replace the motor if that is not the problem. Any help is greatly appreciated.
Emerson belt driven blower fan
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