I have had a RUUD UBHC-21J18SFA air handler for 4 years. The fan runs for a while and then stops and there is a burnt smell. If I let it cool down for a while, it will start again and do the same thing about 30 minutes later. I checked the filters, they are O.K. No major dust accumulation in the unit. I noticed the blower wheel (squirrel cage) has a slight vibration laterally when it spins, sort of off balance, but nothing major, it doesn't rub on either side. The motor becomes very hot to touch while running. I can turn the fan with my fingers when the power is off, and with a slight swing, it will spin for approximately 3/4 of a turn. Somebody told me it should turn 4-5 times around with a manual spin before stopping... I took out the cage and the motor and can turn the motor shaft manually but it seems a little sticky.
Is the problem the motor? or the capacitor? Or is the slightly off balance cage causing the motor to overheat?
Any diagnostic tests I can do myself to find the SOURCE of the problem?
Thanks!
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