Carrier AC keeps tripping breaker - outside A/C unit

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  #1  
Old 06-15-16, 08:15 AM
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Carrier AC keeps tripping breaker - outside A/C unit

This forum has helped me before so I really appreciate it!

The house has been vacant for a few months. I went to turn on the AC and at first heard a humming from the outside unit for a few seconds and then the AC breaker in the house breaker box was tripped. Now when I try to turn it on it just immediately trips the breaker, no more humming sound.

I replaced the capacitor and same result, see last pic below.

Below are the pictures, any thoughts on what else I can replace or do to troubleshoot? Also is it just me or are there no fuses? I know they are usually in the power box but as you can see in the pictures there is nothing there. What am I missing?

Thanks in Advance!





 
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  #2  
Old 06-15-16, 09:10 AM
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That's a typical disconnect switch, no fuses. The contactor looks a little burnt, might be the problem.
 
  #3  
Old 06-15-16, 09:25 AM
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Is the contactor a universal part or is there anything specific about it? Trying to figure out if I go to store will there only be one or 20 for me to chose from.
 
  #4  
Old 06-15-16, 09:43 AM
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Contactors come in 2 general flavors: Single Pole and Double Pole. If you currently have a Double Pole contactor (contactor opens/makes both sides of the 240VAC line), you should use a Double Pole contactor. A Single Pole contactor can be replaced with either single or double pole. FWIW, the only picture I'm seeing is of your quick disconnect box, nothing with a contactor.
 
  #5  
Old 06-15-16, 09:58 AM
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You have a single pole contactor with a 24V coil. Should be able to find it at Grainger's.
 
  #6  
Old 06-15-16, 11:08 AM
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Do you have amp probe/meter?

I would(with power off), disconnect the wires from contactor to compressor and see if it still trips the breaker. If it does, it could be the fan.

But if fan runs, problem is with compressor or the wiring to it.

You can, for testing purposes(to eliminate the contactor), move the wires to the bottom of contactor and basically hard wire it.

If it trips breaker while hard wired, its not the contactor.

If you can, get an amp probe/meter. If compressor tries to start and draws over 102 amps, it may be locked up...
 
  #7  
Old 06-15-16, 12:23 PM
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I went ahead and replaced the contactor and it is still tripping. But I haven't seen this spark type of trip before. Did I wire it wrong? In the shared album below there are pics of the new cap and contactor installed, the wires seem right to me, but maybe I'm missing something?


The following is a link to the shared album:
https://goo.gl/photos/zgTHw9e66qMgspgk7

Also the following is the video of the unit tripping, looks to be a spark...
https://youtu.be/TDRYdjJKwK8

I have a multimeter if someone can explain to me what points to measure.
 

Last edited by cdddazz; 06-15-16 at 01:12 PM.
  #8  
Old 06-15-16, 01:31 PM
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Where is it sparking at the electrical panel or outside?
 
  #9  
Old 06-15-16, 01:38 PM
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Where is it sparking at the electrical panel or outside?
Outside, you can see the spark in the youtube video linked above.
 
  #10  
Old 06-15-16, 01:49 PM
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Skaggsje, it's coming from near the control part of the unit. With that kind of spark you would think you could see black marks.
 
  #11  
Old 06-15-16, 02:02 PM
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I'm thinking maybe I didn't connect the capacitor wires right. The old capacitor was so rusted that I couldn't see which wire was Herm,Fan and C. Is it correct to assume that the yellow is Herm, Fan is brown and C is blue?

This is how it is currently connected with the new cap. I think it's not connected right.

https://goo.gl/photos/iY7jXNG39qjLAbem8
 
  #12  
Old 06-15-16, 02:27 PM
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Yellow is C
Blue is Herm
Brown is fan
 
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Old 06-15-16, 02:30 PM
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I am just guessing without a schematic and a poor memory but I think the blue is herm. yellow common.Follow the blue down to be sure.Got to go back to trimming bushes. Houston beat me to it.
 
  #14  
Old 06-15-16, 02:41 PM
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Yea just checked and the wires are connected fine...what else can I check?

Yellow is to C
Brown is to Fan
Blue is to Herm
 

Last edited by cdddazz; 06-15-16 at 03:15 PM.
  #15  
Old 06-15-16, 03:13 PM
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I would(with power off), disconnect the wires from contactor to compressor and see if it still trips the breaker. If it does, it could be the fan.

But if fan runs, problem is with compressor or the wiring to it.
What wires are the ones that go from the contactor to the compressor? The two yellow ones?
 
  #16  
Old 06-15-16, 03:21 PM
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No, the black and yellow that are connected at the screws. The thicker gauge wires...

Could be just a scraped wire to ground. I think the ground block is close to where the spark was. Hopefully it is just a scraped wire and not an internal compressor issue.
 
  #17  
Old 06-15-16, 03:34 PM
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JJinPA, just to make sure I understand correctly. You are saying to (power off) and disconnect the the black and yellow wires that are connected with the screw only (two front ones in picture below) and then turn the AC on and see if it trips?



The following is a picture of the spark:


Also when you say "Could be just a scraped wire to ground." are you referring to the capped wires that are on the right of the contactor in picture above? (the ones with the blue cap and the red wire?)
 
  #18  
Old 06-15-16, 04:14 PM
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Yes...

The spark is not from those capped wires. Something is grounded that shouldn't be. Just trying to eliminate things...

That spark is headed towards the ground block....

Hopefully its just a bad wire going to the compressor or fan. But could be the compressor or fan motor itself.

Just to make sure we are on same page...Unit trips on call for cooling correct? If you turn on breaker, but do not turn on AC, it does NOT trip breaker, correct?
 
  #19  
Old 06-15-16, 04:36 PM
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Just checked, it does trip the breaker and causes spark even with AC off. Meaning if AC is set to off inside the house the breaker is still tripping causing a spark.
 
  #20  
Old 06-15-16, 05:14 PM
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Ok, that could be a good thing.

You may just have a bad wire in the conduit from the disconnect to the condenser.

With power off, disconnect the feed wires for the contactor(the ones at the bottom), that come from disconnect and cap off...See if unit still trips breaker.

If the disconnect is pulled at the condenser, does it still trip the breaker?

If it does trip with disconnect pulled, the problem is not outside(unless its the disconnect itself, which I doubt).

If it does trip with disconnect on, but contactor feed removed, it is your conduit/wires from disconnect to unit.

Hopefully it does trip with wires disconnected, then it is an easy fix..If it doesn't, then it is back to the compressor/fan/wiring and possible carnage.
 

Last edited by JJinPA; 06-15-16 at 05:53 PM.
  #21  
Old 06-15-16, 06:48 PM
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Between the area that contains your contactor/capacitor and the area that has your fan/compressor is a metal dividing plate. This plate has a hole that the high voltage wires pass through. I've repaired two systems presenting as yours in the last few weeks that had shorts to ground where the wire insulation wore at the hole's edge. This could happen even with no call for cool if you have a single pole contactor as you still have a hot leg. It would also show a spark that matches your video.
 
  #22  
Old 06-16-16, 03:47 AM
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Bottom left are the possible suspect wires fastback speaks of.

If breaker did not trip with contactor disconnected, follow those wires and look for anything charred up/black.

You said you had an electric meter right? If the problem is within the condenser itself, you will need that(unless it is visually obvious) so we can pinpoint the short.
 

Last edited by JJinPA; 06-16-16 at 04:28 AM.
  #23  
Old 06-16-16, 05:18 AM
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Thanks guyold, I see it now.
 
  #24  
Old 06-16-16, 10:40 AM
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I disconnected the feed wires for the contactor (the ones at the bottom, white and black wires) and it did not trip.

Then I connected the feed wires back into the contactor and disconnected one black and one yellow wire from the contactor, the wires that connect with the screw (the front wires) and it did not trip the breaker.

So now the next step is to follow the black and yellow wire that I disconnected above (the ones that screw into contactor) and see if I can find any damage?
 
  #25  
Old 06-16-16, 12:33 PM
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I followed the yellow and black wires and removed the fan bolts to look on the inside. I'm not seeing any exposed wire, I looked in particular where the wires go from the cap area to the inside where the metal is. No cut in the wire insulation or charred or anything.
 
  #26  
Old 06-16-16, 12:46 PM
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Grounded compressor. Sounds like it is time for a new unit.

Unplug the compressor and try it again.
 
  #27  
Old 06-16-16, 12:53 PM
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Unplug the compressor means to do what?

Isn't the compressor connected by the yellow and black wires connected to the contactor via screw that i just disconnected? since it did not trip wouldn't that mean the problem is with either those wires or the compressor? I guess I'm confused why you are saying unplug the compressor and want to understand what exactly that means
 

Last edited by cdddazz; 06-16-16 at 02:20 PM.
  #28  
Old 06-16-16, 03:31 PM
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There's 3 wire connecter that plug's into the side of the compressor.
 
  #29  
Old 06-16-16, 03:42 PM
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Is the following the compressor 3 wire connector? How does it disconnect just pull it?


This is a picture of the bottom of that connector:


Btw what is the purpose of this brown wire on the right? a red and white wire come out of it but they are both separated and have electrical tape on them.
 
  #30  
Old 06-16-16, 04:00 PM
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The red and white wires from the brown cable look like they come from the thermostat. Those are low voltage wires.

The blue and brown look like wires to the fan. Trace them. Where do they go.
 
  #31  
Old 06-16-16, 05:39 PM
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They normally go to the contactor coil, That looks like a 38ck048300 condenser.

Those 3 compressor wires are Herm on the cap and black and yellow using the set screws on the contactor.

I have seen a Carrier 38TDA give me that exact spark with a grounded compressor a while back. It was one a the few times that I wish I had a Meggar since it would not show me an Ohm reading to ground even when she to millions of Ohms.

A grounded compressor will usually show resistance from each terminal to ground.
 
  #32  
Old 06-16-16, 09:08 PM
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I'll remove the compressor connector and see if breaker trips again.

I have a multimeter, how do I check resistance from each terminal to ground? Put the multimeter on resistance and put red end on which terminal? Each terminal on capacitor? What would be ground?
Sorry for the silly questions but I appreciate the help!
 

Last edited by cdddazz; 06-16-16 at 09:33 PM.
  #33  
Old 06-16-16, 09:09 PM
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Sorry

I was hoping it was just the whip or some wiring, but my first thought when seeing the spark was the compressor, with slight hope for fan and faint hope for wiring...You could have fixed anything we eliminated. Now we have hit a bridge.

At least you have a better feel for how it works(or used to) now.

Compressor is probably internally grounded, and you are seeing the current go from the condenser coil(which is just like one huge wire connected to the compressor) to the ground block inside the electrical cabinet. Path of least resistance...and its purpose.

I noticed you also have an R22 unit...I had to make the decision very recently that you may have to make...Replace compressor(plus R22$$) or replace the entire system.
 
  #34  
Old 06-16-16, 09:45 PM
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I don't plan on staying in current place much longer. What would be the path of most resistance to the wallet to get a working AC?
 
  #35  
Old 06-17-16, 05:06 AM
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Why are the red and white wires taped off?
 
  #36  
Old 06-17-16, 11:35 AM
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No idea, that's how it was when I removed the cover.
 
  #37  
Old 06-17-16, 01:40 PM
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With those wires not connected the contactor won't engage. Someone has disabled the AC.
 
  #38  
Old 06-17-16, 04:43 PM
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Can you tell me how are they supposed to be connected?
 
  #39  
Old 06-17-16, 07:32 PM
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I would not connect them. The Sparks that you see are a hazardous condition.
That unit should remain disabled.

The house red wire connects to the condenser blue wire and the house white wire connects to the condenser brown.

That arching can cause serious injury or worse.
 
  #40  
Old 06-18-16, 02:47 AM
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I removed the 3 wire connector from the compressor and the breaker did not trip.

Anything else I can try to check? I have a multimeter, or does this pretty much sum it up that my compressor is dead. It is CR42k6-pfv-220.
 
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