Outside Unit Trips Breaker

Old 11-05-05, 05:51 AM
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Outside Unit Trips Breaker

We have a 4 year old carrier unit that has always worked good. Yesterday the unit was not cooling so I checked the outside unit which was not running, i.e, no fan movement. The breaker by the unit was not tripped but the breaker for A/C in the house panel was tripped. I reset the breaker and adjusted the theromstat to send cooling signal to outside unit. I stood next to the unit and when the outside unit received the signal I heard a single "click" with no fan movement or compressor activity. The outside breaker did not trip but as I suspected the breaker in the house panel tripped. I suspect the following:

a. Circuit breaker possibly bad
b. Fan motor capacitors bad
c. Bad compressor
d. Bad contactors

I am curious as to why the outside breaker does not trip. A/C guy will be coming on Monday so I just wanted to get a few ideas before he comes. Thanks to all for any ideas
Old 11-05-05, 06:12 AM
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Oftentimes, but not always, the ouside disconnect does not contain a real circuit breaker. It is just a switch that looks like a circuit breaker.
Instantly tripping circuit breakers are not the usual way a breaker fails. Circuit breaker failures are usually 1.) frequent tripping while pulling normal amps, 2.) breaker overheats and fails open. While I would still check the breaker, I suspect a short exists in the condensing unit. Check the wiring and everything else in the condensing unit, including the compressor.
Old 11-05-05, 07:43 AM
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I agree with you regarding the circuit breaker in the house and the fact that the outside "breaker" is most likely a simple disconnect. I pulled off the access panel and saw the capacitor and contactor with associated wiring. Everything looked normal except for a poor Gecko that had been obviously "fried" as it came in contact with the capacitor terminals at an inopportune moment. Looking at the schematic I have also concluded the clicking sound I'm hearing is the starter relay. So..given we are tripping the breaker it does appear to be a short. There's really not much wiring to inspect so I'm sort of inclined to believe its a component failure either in the motor windings, capacitor, contactor, or compressor. Gee..not much else is there?

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