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caleb22 · Oct 24, 2007, 07:35 AM

I searched many responses before posting this and didn't really find my answer. So here's my question.

I have a York central air unit and it is around 10 years old (I think, we bought the house last year). The other day the outside fan motor stopped working. I took the capacitor out and had it checked, and it was fine. They told me a troubleshooting technique to test the compressor and the fan.

I hooked the compressor wires to the capacitor and turned it on, without the fan being connected. I heard a humming sound, then I turned it off. Does that mean the compressor is OK?

Then, I hooked the fan wires to the capacitor and turned it on, without the compressor connected. I could hear a humming sound, but it never came on. The fan is easy to turn when not on, but hard to turn when on.

I have a feeling it's the fan motor, but do not want to replace if that is not the case. Any suggestions or troubleshooting tips I can do to narrow this problem down?

Thanks in advance!

Duane in Japan · Oct 24, 2007, 07:52 AM

Hard to turn the fan motor when on, are you turning it the correct way, if yes, is the cap connected the correct way, if both are yes, you should be able to give the motor a good hard swing and it should go. I am trying to remember my old days at Sears repair center, isn't the cap only for the compressor, the fan should go on its own?? There are caps on big motors like for an electrical air compressor, the caps job is to give the motor a kick in the pants to get it started. Give the fan motor a good swing and then give it power, will that get it going.

caleb22 · Oct 24, 2007, 09:24 AM

Originally Posted by Duane in Japan

Give the fan motor a good swing and then give it power, will that get it going.

Thanks, I will give that a try this afternoon. If that does not work, are there any other troubleshooting tips I could try?

Also, I'm not familiar with what the compressor sounds like when the fan is not running. Is that humming sound what it is supposed to sound like? This is my first diagnosis with any central air conditioning system, so pardon my ignorance.

Duane in Japan · Oct 24, 2007, 06:14 PM

Unfortunetly, when the compressor is stuck or when the fan is stuck, they can make a humming noise, they may also burn up the motor while humming.

labman · Oct 24, 2007, 06:31 PM

A healthy compressor will make more of a put, put, put.

tsa7man · Oct 25, 2007, 05:16 AM

First check with a meter to be sure you have the proper voltage to both legs of the 220 volt feed to the cond. Unit ( should be 115 / 120 from one leg to ground on both and across both hot legs 220 volts) The next item to check is the contactor to be sure it is pulling in completely, and the contacts are clean, no bugs, dirt and corrosion etc. ( check with the power OFF to the unit) As well, be sure no wires are loose and or have fallen off their connection points. And you stated the capacitor checked OK, so if it is wired correctly, that should not be your problem. My next question is did this unit / home get hit by a lighting strike ? You could also check the power panel, some older hookups had single breakers for each leg of the 220 volt feed, and one could be tripped...

caleb22 · Oct 25, 2007, 07:40 AM

Originally Posted by tsa7man

My next question is did this unit / home get hit by a lighting strike ? You could also check the power panel, some older hookups had single breakers for each leg of the 220 volt feed, and one could be tripped....

Thank you for your response. To answer your question, it was not hit by lightning. To my knowledge, it just quit working. It's been raining for two days, so I have not been able to check it fully but will try your suggestions as soon as I can.