We have a two-zoned central AC units. The compressor for the upstairs zone works normal. We are having problem with the downstair unit. The compressor some times does not start and some times trips the breaker switch. After replacing the breaker switch (40 Amps) it was running and cooling fine for 2-3 days. This morning I heard it was making a strange screeching noise while it stopped. It was super heated and I felt hot air coming out of it even when it was not running. So I turned it off. Please tell me what might be the reason for the compressor to be hot when it is not running. Is it safe to turn back on?

Could be a bearing going bad in the compressor. After it runs for a while, it heats up and binds. If so, the compressor will have to be replaced. I would largely depend on the theor zone over the weekend, and call a service man Monday. You might try running it short periods, giving it time to cool between. I don't think there is any field servicing of compressors. I doubt you can damage it further, and the new breaker should limit damage to anything else.

I have turned off the system and waiting for a service man on Monday.
I appreciate your quick response.

Could be a bearing going bad in the compressor. After it runs for a while, it heats up and binds. If so, the compressor will have to be replaced. I would largely depend on the theor zone over the weekend, and call a service man Monday. You might try running it short periods of time, giving it time to cool between. I don't think there is any field servicing of compressors. I doubt you can damage it further, and the new breaker should limit damage to anything else.

Bad condenser fan motor