Central Air Trips Breaker

RobSmith

I have a central air unit that is about 6 years old. Starting about 4 years ago the AC started to trip the breaker. Sometimes it would trip it 4-5 times in a single day, sometimes once and done and sometimes it would go 8 weeks with no issues. It is now tripping the breaker frequently. If I let the unit sit for a few hours I can run it for 20+ minutes with no issue. If I turn the unit off at the thermostat, then turn it back on, when it powers back up, it trips the breaker in 2-3 seconds. It almost seems like there is energy being stored up and it is released when the unit cycles back on.

I checked my air filter and cleaned the unit inside and out. I also replaced the breaker. Does anyone have any ideas/suggestions? THANKS!!!

chris75

Too much pressure will cause the motor to work harder raising the amperage and tripping the breaker, I would start with just replacing the breaker, then call an AC tech to check for proper freon.

Yoyizit

the 20 minutes of operation?

Whoever does the troubleshooting, there is equipment that monitors several crucial points in a system like this and babysits the system until the fault occurs, and then dumps the data on what was happening just before the fault occurred, whether it takes seconds or weeks for the fault to recur.
Dranetz is one manu for this kind of equip.
The tech can probably rent a tool like this.

RobSmith

Thanks for the posts.

It always seemed that high humidity days caused me issues.

Last Thursday when I got home the breaker was tripped, I turned it on and it ran fine, cooled the house. When I got up in the morning it was hot and the breaker was tripped. When I got home that night I reset and the unit seemed fine, house was cool when I went to bed but hot when I woke up.

Twice today I turned the air on for 10 minutes, turned off, waited 10 minutes turn the unit on and the lights dim and the breaker pops in under 5 seconds. If I wait a few hours it seems like the unit runs fine. I don't know if it ever pops once it makes it past the first few seconds of startup, and it only seems to pop if it has run in the last few hours. It is the second startup that trips the breaker. The fan runs fine and spins very easily. Other than the compressor going, is there anything it can be?

Yoyizit

Very heavy current being drawn.

A hard start kit, from other posts, will fix?
For the price of a kit, and since there is no downside to installing the kit, it sounds like a good gamble.

8 Ball

How about a few facts...what size is the breaker, what is the max fuse size stated on the unit nameplate, what size wire is pulled to the unit, and how far is it, is the wire copper or aluminum?

Can you, or do you know anyone that can use a volt/amp meter?

Yoyizit

So something has degraded over six years.

Here's one generic troubleshooting strategy for this problem:

If you can't eliminate the compressor motor as a suspect, time to call for help.
Unpower the unit.
You can do this elimination by replacing the six year old compressor motor start capacitor
http://www.topo-capacitor.com/img1/cp-d-2.jpg
or by first checking the existing cap with a DVM, 9v battery and a 50 cent 1 megohm resistor from Radio Shack.
Caps should first be discharged before testing unless they already have a resistor wired across them.

If the symptoms don't substantially change with a new cap, or if the old cap checks good, I'd say it's the compressor.

If a new cap does change the symptoms, for a few more $5's you may want to put a hard start kit in anyway, to take the burden of handling the normally high compressor startup current, from the circuit breaker.
HVAC people on this forum seem to like them, but I'd only put it in once you make sure there is a good cap in there. I think the kit is a help but not intended as a cure for other bad components.