Home AC Compressor shuts off when hot?

Question

I live in Phoenix, AZ. My outside unit (compressor) does not start when it is hot outside (from around 1:00pm to 8:00pm); and if it does then it shuts down soon after. It works normal during all other times. The run and kickstart caps seem to be fine. The outside fan always blowing. So what is causing it not to work properly during the peak of the heat? The unit is 5 years old and always worked fine. No freezing either during that period of time. Could it be that the "radiator like" or coil section of the compressor needs cleaning? although it did not look anymore dusty then last 5 years.? or could it be that the compressor is going out and it's first symptom is not to work properly when it is too hot? Please help. Thanks.

Answer 1

The outdoor fan and compressor control are on the same contactor. If the unit is calling, and the compressor is not starting, it is out on internal heat/pressure overload. I think you've diagnosed the problem yourself; the coil is clogged.

A coil cleaning is easy to do. Use a gentle garden hose and wash down the coil. You'd be amazed at how much dirt the things hold. Don't be tempted to blast the fins; these can bend over easily, you just want to wash away the fine particles of dust that are blocking the transfer of heat energy to the air. A good 10 minutes with a gentle hose should do it.

If it still does not respond, you'll have to call in a pro.

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