Having a problem with my ac compressor fan. Unit starts fine and produces nice cool air. Problem comes when it reaches thermostat temp after a few hours and it cycles off. When the temp rises a few degress and tries to cycle back on, the compressor fan won't turn and it makes a humming noise like it is trying to but can't.

Possible capicitor

When it tries but want start, turn off the power,spin fan blade with a stick,does it seem to be kind of stiff hard to turn ? Or does it spin freely?

The blades seem to spin fine. In fact, if I turn it off for an hour and let it cool down, it will start back up fine and work for a few hours again until it cycle off. When it tries to start back up, same thing.

Also, my current heating/cooling guy is trying to tell me that he thinks the freon is corrupted with water or air and should be vacuumed out and replaced ($900 or so... ). That doesn't sit right with me. Don't see how a freon issue would effect the compressor fan. Oh, and thanks for the reply.

Quote:::work for a few hours again until it cycle off

Does it run that long before it satisfies the tstat and turns off?

Not always. Since we've been having this problem I've been using it sparingly. The thermostat for the second & third floors is, unfortunately, located on the third floor (converted attic) which gets rather hot. I've been keeping it off during the day and turning it on a hour before the kids go to bed as I can't trust it to make it through the an exteded period without the fan shutting off. When it was working properly, no, I don't think it took that long and it would cycle on/off for far shorter periods.

Just a bit more detail if anyone is listening. Managed to catch the fan right as it was trying to restart. Would turn about a quarter revolution and stop. When I tried to push the fan, there was quite a bit of resistance. Once I turned the a/c off, the fan spun freely. Thinking this must mean it is not the capacitor and is probably the fan motor or the bearings inside...

Probably a good thought
Keep in mind when you get a new motor ,it will need a new capicitor that matches the motor,its just a small one that is for the new motor only,leave the bigger duel cap for the compressor to run on