HVAC help

[Elite0429]

What y'all think? My ac unit worked fine all day yesterday, went to have dinner at 5 pm returned home at 730 pm and only the indoor unit was running, outside unit was NOT. 1st checked breaker for outdoor unit and it was tripped. I reset the breaker and turn ac back on to cool. Still outside unit not running, compressor is humming, but fan motor did not kick on. I had a spare start capacitor that I quickly changed out and same thing. Compressor comes on but fan motor does not start. Would my next and only other option is a bad fan motor? Fan motor amped out and tripped breaker while I was gone? Any help or input appreciated

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[Pigkilln]

I had to cool mine with a water hose after the capacitor change out. Same thing outside wouldn’t run and was told it was high temp keeping it from starting. Try that before replacing anything. Good luck

[Muskles]

Mine has done this before. See if you can turn the fan blade on the outside unit with a stick. Or turn it off and pull the top off and turn it by hand. The motor bearings were out on mine. The fan was hard to turn. You could spin it with the unit on, and it would start. When it shut itself off, it would do the same thing when it would try to start the next time.

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[Elite0429]

Mine has done this before. See if you can turn the fan blade on the outside unit with a stick. Or turn it off and pull the top off and turn it by hand. The motor bearings were out on mine. The fan was hard to turn. You could spin it with the unit on, and it would start. When it shut itself off, it would do the same thing when it would try to start the next time.

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the fan motor spins freely, I tried this last night

[bowshooter1994]

Hey bud, I'm actually an air condition technician. Hope my advice can help. I heard you say compressor is humming or working. If working sounds like you just need to change the fan motor or the wires are shorted. Your motor can short internally and also trip your breaker. If your in the Austin area check out Hamilton electric. If your compressor is not turning over check voltage at the contractor where high voltage is coming in. Should be 208-240. Might be ants in that contactor. If so it's bad. You said you put in a start capacitor. You might need to try and replace the "RUN" capacitor. Some people get that confused so I don't know if you already did that. If nothing is a sure sign after that email me maybe I can help.

[bowshooter1994]

[QUOTE=bowshooter1994;13284058]Hey bud, I'm actually an air condition technician. Hope my advice can help. I heard you say compressor is humming or working. If working sounds like you just need to change the fan motor or the wires are shorted. Your motor can short internally and also trip your breaker. If your in the Austin area check out Hamilton electric. If your compressor is not turning over check voltage at the contractor where high voltage is coming in. Should be 208-240. Might be ants in that contactor. If so it's bad. You said you put in a start capacitor. You might need to try and replace the "RUN" capacitor. Some think run and start are the same. I don't which you did. Good luck

[BTLowry]

Mine was a capacitor, had very similar symptoms

If you have a meter you can check the capacitor and see if it is good or bad

[Elite0429]

Hey bud, I'm actually an air condition technician. Hope my advice can help. I heard you say compressor is humming or working. If working sounds like you just need to change the fan motor or the wires are shorted. Your motor can short internally and also trip your breaker. If your in the Austin area check out Hamilton electric. If your compressor is not turning over check voltage at the contractor where high voltage is coming in. Should be 208-240. Might be ants in that contactor. If so it's bad. You said you put in a start capacitor. You might need to try and replace the "RUN" capacitor. Some people get that confused so I don't know if you already did that. If nothing is a sure sign after that email me maybe I can help.

yes compressor is working as I hear it running/ humming. I turn ac off, the compressor turns off. and I might have meant the run capacitor. I have a large cylinder and smaller oval/oblong shaped one. the smaller one I changed out as it goes to the fan motor

[JhuntsAlot]

Mine was a capacitor, had very similar symptoms

If you have a meter you can check the capacitor and see if it is good or bad

I had a 5 year old system do the same. Changed the cap and worked great. Since I was in there I added a hard start capacitor as well. That helped with the lights dimming when the compressor kicked on.


J

[AntlerCollector]

I've had this happen to me and it was the fan motor

[be12hunt]

yes compressor is working as I hear it running/ humming. I turn ac off, the compressor turns off. and I might have meant the run capacitor. I have a large cylinder and smaller oval/oblong shaped one. the smaller one I changed out as it goes to the fan motor

Try changing the other cap out as well. The smaller one is a start capacitor and the larger is your run capacitor. If it’s bad the fan may or may not come on. It will definitely not be running right.

[Elite0429]

Try changing the other cap out as well. The smaller one is a start capacitor and the larger is your run capacitor. If it’s bad the fan may or may not come on. It will definitely not be running right.

I guess this may be my next move. how can I actually tell if the compressor is actually running or just making a noise? I assumed that if I heard it making a noise it was running. but now im reading that may not be the case.

[double bogey]

If the compressor runs without the fan the coil will be hot, and the small line will be hot or warm. The small oval capacitor is most likely for the fan. Sometimes the contactor will be noisy enough to be confused with the compressor. If the contactor is that noisy, it may not be working or have ants in it. If you know how to work a voltmeter I can tell you a few things to check.

If you try to spin the fan motor with the unit energized be careful, if it is shorted you could get a nasty shock. Over 40 years in the hvac business and the worse shock I have ever had was from an improperly grounded fan motor when I grabbed the shaft to see if the bearings were bad.

[double bogey]

Most units made in the last 30 years or so have a dual capacitor in the outside unit. They will have 3 terminals. A "common" terminal, a "hermetic" terminal, and a "fan" terminal. Sometimes when a fan motor or capacitor is replaced the tech may not have proper dual capacitor on hand. Therefore he may have to use separate capacitors. Totally ok to do this as long as they are the correct size and are properly secured. Start capacitors are almost always round and black plastic and accompanied by a start relay.

If you have a voltmeter with a capacitor function on it you can test your capacitor. Beware, capacitors will hold a charge, and while mostly aren't fatal, the can cause an unscheduled change of underware. Never touch any wiring inside your unit without checking for voltage first. Disconnects don't always work.

[Smokeater]

Like he said. Fire ants love those contactors! Make sure your getting all your voltage thru all legs.