How easy should a squirrel cage furnace blower fan spin? I can’t get it to run with the A/C so I tried to spin it by hand and it seems to spin easy. Bad motor bearings?
thanks,
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another thread going on on the same subject so watch it.
yes, the fan spins pretty freely,spin it with your hand good ,should continue spinning for maybe 30-45 seconds.
like the other thread ,does it run in furnace mode? if it doesn't look at fan motor or the motor capacitor. if it runs on furnace look at the other thread going on.
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I think we're having the same problem. Sounds crazy, but see if the blower works when the heat is turned on.
With the belt off? or is this direct drive? Belt off ... should spin easy. Belt on ... eh not sure. Direct drive? Can somebody help us out here?!
If the blower cage makes a couple of revolutions after you spin it, then the bearings should be ok.
Is it humming and getting hot? Probably a cap. then.
If it's not getting power then there is a litney of possible fixes.
More info needed.
Should spin easily by hand. If direct drive (no belt) will continue to "coast" for tens of seconds. Belt drive won't coast much but should still easily spin by hand.
The most common cause of failure to start is a bad start capacitor or mucked-up start contacts in the motor. If the motor hums but doesn't start (and eventually gets warm enough to trip its overtemp sensor) then a bad cap or start contacts is the likely cause.
Otherwise, on a conventional setup (without electronic controls in the furnace) the fan relay is suspect. You should be able to hear/see it "close" when the "fan" switch on the thermostat is switched (with AC turned off). (On our old furnace the fan relay would physically fall out of its socket about once every 4 years, as it worked loose due to vibration.)
Finally, the thermostat can be at fault. In AC mode the thermostat is responsible for telling the fan to come on, and if the thermostat is defective (or a wire has broken) the AC can come on without the fan.