I'm having a wired problem with my A/C. The air coming out of the indoor blower goes through a cycle of blowing cold and blowing warm, instead of consistently cold - 15 minutes of blowing cold air followed by 20 minutes of warm air, and then again 15 minutes of cold air. This keeps on repeating over and over.

After some close monitoring, I discovered that the full cycle of the problem goes like this:

1. A/C turns on per thermostat setting and blows out cold air.
   
2. After running 15 minutes or so, the compressor fan motor shuts off (overheated, I believe). The indoor blower is still blowing cool air.
   
3. Shortly after the compressor fan motor shuts off, the compressor overheats and shuts off. The indoor blower now starts blowing warm air.
   
4. After like 20 minutes or so, the compressor fan motor comes back on (I assume because it has cooled down).
   
5. After a little bit, the compressor comes back on (cooled off by the fan), and the indoor unit starts blowing cool air again.
   
6. Cycle continues steps 2 through 6.

All during this sequence, the air handler/blower inside the house is running non-stop, and the room never reaches the set temperature.

I have had my A/C company check my unit thrice.
During the 1st visit, they charged freons and cleaned the coil thoroughly. That worked somewhat, but just after a week of operation the problem showed up again. In their 2nd visit they changed one of the capacitors - the system has 2. Didn't solve the problem. When I called them for the 3rd time, they said the compressor fan motor was turning slow and needed to be repaired or changed. I had it repaired, but it didn't gain speed nor the original problem was solved.

And by the way, if I run a water sprinkler outside over the compressor unit including the fan motor, everything works perfectly.

No one I have spoken to about this has any idea of what could be causing this problem. My A/C is 3 years old. Never had any problem of any kind with it before this.

Anyone have any ideas?

Many thanks

 

Welcome to the forums.

It sounds like they're guessing around the problem.

They changed "a" capacitor but was it the one for the condensor fan ?
It appears that the condensor fan motor is bad. (if they did change the right cap.)

 

Thanks for replying, PJmax!

The fan is connected to a small 2uF capacitor, while the one they changed was a 40uF cap. However, they tested the fan capacitor and said it was fine.

 

Whenever there is a motor starting issue.... the capacitor is changed first.
They changed the compressor cap which would not affect the fan motor.

 

Sounds like a fan motor problem, as you mentioned, overheated. A new fan motor may fix your problem.

 

Unit under warranty keep calling them back Dispute any bill that does not fix it. Start looking for a good HVAC company

 

If running a sprinkler over the unit keeps it running, then obviously something's overheating.
The fan motor is first to shut down, so it's the problem.
Have the fan motor replaced.