Curious about central AC problem

Not mine -- a central air unit at work has failed, and the compressor supposedly just hums a lot. That's all the detail I have. No smoke, no tripped breakers. We have a maintenance crew to solve this.

I'm wondering -- in a typical AC system, what happens if / when the blower fan on the compressor fails? I don't mean the compressor unit itself, just the fan that blows air across the fins to cool the refrigerant. If that fan dies, would the system 'know' to shut down, or would the compressor keep running? In that case, since the refrigerant is still carrying almost all of its heat, could the compressor even get it back to a liquid? Is that fan also critical to cool the compressor?

I'm just wondering if the failure of one component can lead to the destruction of another; if the fan quits, does the compressor just run until it overheats and dies?

Reply to
Robert Barr
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There "should" be a high temperature switch on the compressor. But very often they do overheat and die.

Reply to
Stormin Mormon

MANY systems have both over and under pressure shutoffs. The most likely problem on the AC compressor is a bad starting cap or relay. Many compressors are "impedence protected" in such a way that the motor will not be damaged right away when the motor hums and fails to start.

Reply to
clare

If the fan quits it can cause a high head pressure situation. There should be a high pressure cutout to cut off the compressor.

Reply to
Ralph Mowery

HOWEVER repeated cycling can cause problems in the breaker/fuse panel . My son ended up replacing his fuse box with a modern breaker panel after the start cap died on his central air . It cycled repeatedly , causing the fuse panel connections to overheat , fried the terminals on that circuit .

Reply to
Terry Coombs

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