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Discussion Starter · #1 ·
I was called out to a moble home that the blower motor stopped running. I went to the force air unit and jumper it to start the blower motor and it started to hum. So I check the Run Capacitor and it was good. So I took of the Blower assembly out and took it to the shop. I wired it up to check it and it worked great in all speeds. So I brought it back and hooked it up and it did the same thing....Hum. Thought it might be the fan relay so i by passed it and it did the same thing. Then I wired it up again to plug it in to a wall plug other then the dedicated circuit for the Air Handler the same thing happen. Then I went to the Moble home next door and plug it in there and it ran fine. The outside 220v compressor works fine so I know there is no problem there. I check all the connections in the panel box to make sure they are tight and they were. Could it be a bad neutral coming from the utility company to when I switch the blower motor on it drops out just enough to make it not start? The strange thing is why it works everywhere but in the home.
 

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Head Grunt
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3,270 Posts
X2, may be a loose connection or corrosion problem. Load test the wire and check for voltage drop or as said check the voltage while the device is under load. It may be possible that the fan circuit and this other plug circuit are one in the same? If there was a problem with the neutral coming into the home then you would have more problems than just this fan.
 

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NICKTECH
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273 Posts
a dead neutral would not complete the circuit and you wouldnt get a hum. is the AH 110 or 220v? ask the HO if there was work done recently. if 220 ya might be getting 1 phase instead of two L1 + L1 = 110 ya know. good luck
 

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Most mobile home electric furnaces are 220v. Check voltages & be very careful to not let the smoke out of the motor. Once the smoke is gone, you need a new motor.
 

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ampman
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783 Posts
X2, may be a loose connection or corrosion problem. Load test the wire and check for voltage drop or as said check the voltage while the device is under load. It may be possible that the fan circuit and this other plug circuit are one in the same? If there was a problem with the neutral coming into the home then you would have more problems than just this fan.
x3 when you put a meter on the line and it shows voltage dont mean anything unless its under a load
 
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