Compressor works fine, trips circuit breaker AFTER the next startup:


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Old 08-06-10, 01:02 AM
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Compressor works fine, trips circuit breaker AFTER the next startup:

So the outside unit started tripping the breaker. I am not saavy with these things, but am a careful tinkerer; started with replacing a breaker. Did not completely solve the issue. I cleaned/tightened some other connections (sort of secondary breaker box close to the unit in the backyard).

The strange thing is, AFTER doing these, it runs PERFECT, but only as long as I keep it running.

In other words, if it "auto" shut offs after reaching the certain temp on thermostat, and then later kicks back up again, it trips the breaker immediately (and consistently, atleast for 10x cycles).

Reset the breaker and it runs PERFECT again. As long as I need it, literally. On the next "reboot", boom, circuit breaker pops.

What on earth could be going on? I've done what research I can but in this case I am baffled!!! I've seen some indication that it might be a "check valve" that needs cleaning/lube, but I could be way off base here.

Any suggestions? In return, I offer virtual cookies and any computer, website, general geek advice you need.

Unit: Trane XE 1100
 
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Old 08-06-10, 07:27 AM
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Does it matter how long between shut down and start up?

If the compressor shuts down and then restarts in 15 mins the breaker trips. If the compressor shuts down and doesn't restart for 5 hours, does the breaker still trip? I'm not an AC guy but I'm wondering if there is something that relives the head pressure that is not doing its job.
 
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Old 08-06-10, 07:32 AM
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Did you say you can start the unit manually without poping the breaker (everytime ?)?
 
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Old 08-06-10, 08:26 AM
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Thanks for replies.

Once the breaker trips, I have to turn the breaker to off, then to on ; after that point it runs fine for however long (hours) until the thermostat turns it off. If the breaker trips, I have to reset breaker, but then it works.

The condition that seems to cause the trip, is the RESTART of the unit. That's the confusing part. I welcome suggestions (LoL, other than let it run 24/7) : I am unsure if the time between restarts matters, but I haven't noticed any difference if I switch it manually off, then to on, or let it sit for an hour before restart; seems to trip breaker ALL the time. Could this be pressure-related?
 
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Old 08-06-10, 09:36 AM
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Here is my theory. When auto turn on, the 'contactor' must be pulled in, but if you just reset the breaker, the 'contactor' was already pulled in. Everything else should be the same. So I think the problem should be at the split second when the contactor is pulled in. I'll check the contactor make sure it is clean, tight, and in good shape (this is my guess only).
 
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Old 08-06-10, 10:13 AM
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I'll double check; everything I find on contactor-related issues seems to indicate that staying ON no matter what would be the issue.

I don't know if it helps any, but it seems if I release pressure from the tubes running into the bottom/side of the unit, this allows the startup after resetting the circuit breaker... that's why I'm thinking maybe it's something pressure-related and this "check valve" that I read about. Any confirmation? I'm sure I'm not supposed to release pressure this way, was just poking around.
 
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Old 08-06-10, 10:21 AM
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Originally Posted by kcrinklaw View Post
I don't know if it helps any, but it seems if I release pressure from the tubes running into the bottom/side of the unit, this allows the startup after resetting the circuit breaker... that's why I'm thinking maybe it's something pressure-related and this "check valve" that I read about. Any confirmation? I'm sure I'm not supposed to release pressure this way, was just poking around.
This is along the lines that I am thinking but IDK why the breaker tripping would have anything to do with the head pressure. You do not want to be releasing the pressure that way because you are losing freon each time you do it.

Just wondering, what size breaker is it, what size wire is it fed with and what is the max size breaker or fuse listed on the nameplate of the unit?
 
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Old 08-06-10, 01:06 PM
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seems pretty consistent that the breaker now trips ONLY after a restart; Now, though, simply resetting the breaker does allow it to run without any pressure release currently (although prior to releasing the pressure, this did not work). (I was just experimenting, I know messing with the refrigerant/pressure release is typically a no-no, but some of my symptoms prior indicated possible over-charge? So was checking this). It seems to have helped but is no longer required. (I read that overcharge on a HE unit can cause it to work harder, therefore drawing more amps/tripping breaker).

So may be somewhat related, but not sure; surprised that it seems to have helped.

I have replaced breaker prior (current one is new, same brand/amps/shape as prior), was inexpensive and possible solution so I went for it. Breaker is a 50amp, panel on unit lists 50amp recommended, 50amp max. w/ 30 line amperage max: while I do not know the guage of the wires; from the breaker box they appear fairly thick, twisted, and in good condition; I know thicker means > amperage, so I imagine this to be ok.

Still stumped, but the prior pressure release allowed it to run ONCE after a restart, all the way through. It tripped again next restart. While I'm curious WHY this would matter, it seems to have helped and I'm further curious if there isn't still an over-charge issue at play, or something else related?

I don't believe it to be strictly electrical at this point; the circuit breaking is a "symptom", the puzzle is WHY does it do it ONLY after the restart, but not after a "breaker start" start-up....

Your expertise is very, very kindly received and thank you for any further advice.
 
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Old 08-06-10, 02:06 PM
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I still think the contactor is your problem since the auto start pulls the contactor, the breaker start does not. To verify this, you can do this :
Disconnect 24V from the contactor, push the contactor in with an insulated scraw driver, this should trip the breaker. then go ahead reset the breaker(it won't start since the breaker is not in), then push the contactor again, it should trip again. Now this time you hold the contactor in, have some one else reset the breaker, the system should start.. If the above are all true, that indicates the contactor start is the problem..
 
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Old 08-06-10, 03:09 PM
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We MIGHT be on to something. I admitted to NOT looking at the contactor earlier because the symptoms didn't QUITE fit (also, not having a CLUE where it was and/or not wanting to risk electrical damage by opening the unit), BUT I actually looked after some prodding from clocert and discovered an obviously popped "start" capacitor, a "Kickstart" 270-324MFG with some lovely brownish, white crusted liquid seeping from it! I will update if this seems to be our answer, and have appreciated the knowledge shared so far! Lesson learned: pop the panel! Update later.
 
 

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