central air tripping breaker


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Old 09-07-08, 10:09 PM
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central air tripping breaker

here's my problem my central air unit has started trippin the 30 amp breaker. the unit was put in in 95. I changed the breaker and that didn't help so I called up a friend who installs them, and he ended up changing the starter cap b/c it was arcing and he also changed out the relay and contact. He checked the current on all the wires and freon both were ok. I thought that the problem was fixed but it has tripped the breaker again. I have noticed that it has been turning on probably 10-15mins after it shuts off. I set the thermostat up a little to try and keep it from basically turning on and off...can anyone give me an idea what might be causing this
 
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Old 09-08-08, 07:10 AM
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You have a short. most probably is your fan motor or compressor. you can check the inside fan by using 'fan only' to see if that is the problem. outside fan and compressor work together, so you may have to call a AC tech, they can check them separately to find out where the short is.
 
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Old 09-08-08, 08:16 AM
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thx got the tech out here and he wants me to put in a 40 amp breaker where the 30 amp was same size wire that is going to the 30amp is going to a 50amp above it for my stove he wanted to put in a 50 his reason his that the compressor is tight. he checked start up amps also and also need to change my thermostat have mercury one and going to digital
 
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Old 09-08-08, 08:40 AM
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May be the compressor is geting old, it draw more current now, otherwise why have it run 13 years without any problem.
T-stat should have nothing to do with this problem, but it is an upgrade anyway.
 
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Old 09-08-08, 10:02 AM
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A C Repair

You size breakers according to wire size not the equipment draw if you have #8 strande wire then you can upsize your breaker if that is #10 solid wire you will start generating too much heat and you will burn something up (maybe your house)
it sounds to me like you are overamping and there could be alot of causes, did he clean the outdoor coils, has anyone checked the superheat to make sure you are not flooding back and trying to pump liquid, do you have the right cpacitors on the compressor and has anyone put a hard start kit on it. these are all questions that need to be answered before upsizing any breaker and possibly creating a fire hazard.
 
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Old 09-08-08, 10:46 AM
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the wire size is the same as what is on the 50 amp breaker for my stove plus he said wire was rated up to 50 amps also the unit is on a 40 amp breaker outside a 30 amp breaker was supplying a 20amp for my air pump and a 40 amp for unit. but that didn't work either it tripped the 40 am breaker outside so called him back out here and took off the fan to get to the compressor and found a mouse was on the connections going to the compressor being has the mouse still had fur on it he may have been the culprit hopefully we shall see
 
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Old 09-08-08, 10:50 AM
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hard start w/ new relay and contact was changed out yesterday
 
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Old 09-08-08, 12:28 PM
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If the unit has been running for 13 years, I would not blame on the wrong size of wire or wrong breaker amp. Also, the unit can run for 15-20 minutes before stop, there must be something slowly(take 15 minutes) get to that point to trip the breaker. And i really don't think a mouse can do that. By increase the AMP and the wire size, you may accommodate the increasing current requirement now, but you did not fix the problem. Did the AC tech say which component requires more AMP now ? He said compressor is tight, what is that mean ?? (I had a Chev car burn the fuse after I turned AC on for about 10 minutes, every time on time, turns out to be a bad compressor, when temperature rises to a point, it shorts, well, this is just a different example, Hope your compressor is Ok)
 
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Old 09-09-08, 10:51 AM
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guess the mouse was the culprit b/c now the breaker is not being tripped....now when the unit comes on there is a buzz coming from my c.b. panel...the new breaker that was put in is not the one that is buzzing...this only happens when unit comes on it's a quick buzz.....then stops what could this be? thx
 
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Old 09-09-08, 07:58 PM
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I don't know what cause that buzzing, but I surely don't like it.
may be someone else can help you.
 
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Old 09-10-08, 09:14 PM
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believe the problem has been found the the windings on the compressor is what's causin the buzz sound. had an electrician come out today and changed the breaker out to a wider breaker but was told that the compressor is going out and causing more amps to be drawn b/c of the windings in the compressor do now i am going to have to buy a new unit....
 
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Old 09-11-08, 03:34 AM
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At 13 years you're due for a new system anyway. Be sure and get a few bids and a load calc with each one.
 
 

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