a/c doesn't turn on, only makes noise


  #1  
Old 08-01-11, 06:31 PM
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a/c doesn't turn on, only makes noise

My outside unit doesnt kick on at all, only get a buzzing/humming noise and a few seconds later the breaker trips.

Can someone tell me where the "contactor" is located or what it looks like? Thanks!
 

Last edited by hvactechfw; 08-01-11 at 06:41 PM. Reason: started new thread instead of hijacking an old thread
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Old 08-01-11, 06:44 PM
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I would first check the capacitor and or look for burnt wires. The contactor is what allows voltage to be applied to the compressor and motor. The breaker would only trip if you have a short or if the compressor or fan motor were pulling too many amps.
 
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Old 08-01-11, 06:46 PM
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contactor is inside the unit behind the main panel. you will see the electric from the main panel go into the electrical cabinet. has 2 wires going into the bottom and atleast 2 from the top. if you attempt to repair, you will be looking for something in the compressor circuit. thats the only thing that will pull enough amps to trip the breaker after a few seconds. if it was grounded, it will trip almost instantly. your compressor is probably pulling LRA (locked rotor amps) for too long causing the trip. investigate and tell us what you see and find.

also check the wires going directly into the compressor. after a while the tend to wear out and eventually they may loosen up enough to where they will pop off when the unit is started and direct ground causing the trip.
 
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Old 08-01-11, 07:25 PM
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thanks for the tips i will investigate further tomorrow in the a.m. and report back what i find. Thanks!
 
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Old 08-02-11, 11:05 AM
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After looking everything over and checking online what a bad capacitor looks like. Pics i saw online.




Mine didnt look anything like that so i assumed it was good and called up an AC repair man cause i was not comfortable proceeding any further. Well he shows up, looks at everthing for about 2 mins and said i have a bad capacitor. I was like wtf. Anyway he told me even the slightest bowing under the terminals is an indication that the capacitor is bad. So he leaves for 10 mins to get the part, comes back and installs it and BAM, my AC is blowing cold air again. The whole process took about 25 mins. I was charged $118.88 for parts/labor.

Pics of what my Capacitor looks like. Looked fine to me, lol. But it was not, anyway this is more info for the DIY'ers out there, thanks for the help.

 
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Old 08-02-11, 11:10 AM
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$118 is a pretty good price.

Yep...any bulging of the top means it's shot. Should look like a soup can...concave or flat. Any convex shape means it's got issues.
 
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Old 08-02-11, 06:43 PM
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That is a GREAT price!......................
 
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Old 08-03-11, 12:28 AM
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Yep i agree on the price, i was shocked when he gave me the invoice i was expecting it to be higher.


I was charged $90 for labor and $25 for the Cap plus taxes.
 
 

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