Carrier blower motor problem - http://www.hvacmechanic.com/ Forums
Original message
| Velodog2
 |  "Carrier blower motor problem"
, posted Wed 25 Jun 16:16  
I have a Carrier model 40AQ036310BU that appears to have a non-functioning blower.
I had problems last year where in the spring I turned the system on and the blower motor only hummed loudly but wouldn't move. After a minute or so it thermally shut down. I had the mechanic out and he took the panel off and nudged the motor whereupon it started turning and he laughed at me for paying him $80 to nudge it. He said it was corroded and would need to be replaced. The unit stopped a couple of times during the summer but restarted by itself eventually.
This spring same issue, but no fixing it. I nudged it, but it didn't help. The motor is definitely getting hot when it is turned on but not running which is causing the thermal shutdown. The fan turns freely so I don't beleive the initial diagnosis of corrosion, at least on the bearings, is correct.
I tested the starter capacitor and it is not shorted.
Do I need to replace the motor?
I noticed also when near the unit that even with the thermostat switched to off, there is a slight hum coming from the unit. I have no idea what this means. Then a few mornings ago, with the thermostat again turned off, I woke to the unit humming quite loudly. I turned the power off at the breaker. I have no idea what any of this may indicate.
Any help out there?
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Replies:
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| oldmangobles
| "Re(1):Carrier blower motor problem" , posted Wed 25 Jun 18:41
does the capacitor have the correct microfarad reading?is this what you tested?if the capacitor is well below or above the intended microfarads it will not start the motor.
old man mike
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| | Velodog2
| "Re(2):Carrier blower motor problem" , posted Thu 26 Jun 08:47
No I'm not that sophisticated. I just checked to see if the cap was sucking all the power away from the motor. If the capacitor was bad would the motor still start if manually pushed?
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| | Freon
| "Re(3):Carrier blower motor problem" , posted Thu 26 Jun 10:49
First turn off the power. Open the blower door so you can see the motor and squirrel cage. With your hand, spin the squirrel cage and listen. Does it spin freely and quietly. If so, the bearings are probably ok.
Look for the run capacitor. It's usually oval with an aluminum case and two wires. Remove it and go to the HVAC store and buy a new one ASAP. Don't run the motor until you do. And if it is a dying capacitor and you have power to the motor, a little manual push oon the squirrel cage will get the motor to spin but don't let it run in this condition... get the new capacitor.
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| | Velodog2
| "Re(4):Carrier blower motor problem" , posted Thu 26 Jun 14:41
Freon
The squirrel cage spins freely. I tried starting the motor with a manual push on the squirrel cage with power to the motor but this did not work, although apparently it did last spring when the service tech did it. If the cap was dying last year, then it ran all season in that condition. Could this have fried the motor somehow? How?
What about the humming coming from the unit? What could cause that?
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