Outdoor HVAC Unit Fan Motor Does Not Work

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tom baker

tom baker

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Got a call from my son, the fan on his outdoor HVAC condenser does not work. this is in a Payne PH12NA036B, serial number shows it may be new in 2002. Would it be a bad capacitor or motor? The motor still turns
Failed last week in western washington when it was over 100 deg. I probably can get parts, and try to fix. I own the house and he rents from me.
 
tom baker said:
Got a call from my son, the fan on his outdoor HVAC condenser does not work. this is in a Payne PH12NA036B, serial number shows it may be new in 2002. Would it be a bad capacitor or motor? The motor still turns
Failed last week in western washington when it was over 100 deg. I probably can get parts, and try to fix. I own the house and he rents from me.
Click to expand...
It could be a lot of things. Does the compressor run? If so, it could be the fan motor, capacitor or control relay.

1. Check voltage at power leads going to fan motor. If there's 240 there then you know it's the motor or capacitor. If there's no power then it's the relay or control board.

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petersonra said:
If you energize the motor and turn it by hand does it start running by itself?
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These are typically PSC motors and though it might try to run when doing that it generally won't keep running as it needs the phase shift created by the capacitor to create the needed rotation in the field windings.

These motors also typically have sleeve bearings and rotor may turn freely when not energized but may have too much play when energized and pull the rotor far enough one direction to contact the stator if the sleeve is too worn.
 
If the compressor runs and the fan doesn't and it turns freely I can almost guarantee that it's the capacitor. But the first thing you should do though is get out your meter and see that there is voltage on the motor leads. There should be a schematic pasted somewhere in the cover so that you can see which to check. If you have a meter that will check capacitors for value like my Fieldpiece meter, have at it. But it's probably just as easy to just replace the cap.

-Hal
 
tom baker said:
I own the house and he rents from me.
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As a landlord myself and a electrician who knows nothing about hvac units I would call a Hvac service person who probably knows whats wrong with the unit has the part on his truck or can get it.
 
Yes I agree we have a call in to an HVAC company, they will be there July 17th. The house is 80 miles away but if I can find a capacitor I will get one and change it out. Need to visit anyway.
And if the HVAC system is 20 years old it may be time to replace.
 
tom baker said:
Yes I agree we have a call in to an HVAC company, they will be there July 17th. The house is 80 miles away but if I can find a capacitor I will get one and change it out. Need to visit anyway.
And if the HVAC system is 20 years old it may be time to replace.
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July 17th? Wow... there's a heatwave going on there now too isn't there?
 
Most HVAC have a 3 terminal capacitor that is the run cap for both fan and compressor.
If both fan and compressor not running, almost certainly the capacitor.

Where is your son in West WA, if in/near Renton I'll drop off a cap at his house for you <G>.
It was crazy here last week when it hit 114F - broke all time records by over 10F. A grandson shelled out $600 for a ducted window shaker as hi apt did not have AC and was 95 inside even opening all the windows doors at 5 AM to cool the apt.
 
Nice, he is in Centralia. I am going to see if I can find one tomorrow. I will try Jensco to see if they will do a cash sale at the counter
 
tom baker said:
Nice, he is in Centralia. I am going to see if I can find one tomorrow. I will try Jensco to see if they will do a cash sale at the counter
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If you go to a HVAC supply house see if you can get a capacitor that's made is the US, not China, it should last much longer. If you watch HVAC videos on YouTube, many of the HVAC guys hate the made in China caps.

If you have a mulitmeter that can measure capacitance you can test the capacitor. Lacking that, as others have said, just replace it.

If the outside fan does not run but the compressor does, the liquid freon line (the smaller of the two copper pipes going from the outside unit to the inside unit) will get very hot very quickly. Then the compressor should shutoff, due to high head pressure.
 
robertd said:
If you go to a HVAC supply house see if you can get a capacitor that's made is the US, not China, it should last much longer. If you watch HVAC videos on YouTube, many of the HVAC guys hate the made in China caps.

If you have a mulitmeter that can measure capacitance you can test the capacitor. Lacking that, as others have said, just replace it.

If the outside fan does not run but the compressor does, the liquid freon line (the smaller of the two copper pipes going from the outside unit to the inside unit) will get very hot very quickly. Then the compressor should shutoff, due to high head pressure.
Click to expand...

Can test for shorted or open capacitor easily with ohmmeter. Majority of failures will be one of those two things on most motor capacitors, or terminal pulling off the unit is also pretty common.
 
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