A/C problem, need help ASAP

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I have a central A/C. Around when there was a thunderstorm, electricity flickered about 2-3 times in our house.
Now our A/C is not working. The inside is all fine, the fan runs etc.
I am doing investigation and will post in this thread, but the breaker popped and any attempt to reset it pops it again. I tried to measure amps with my ammeter, it was quite hard to do due to breaker popping soon, but the highest measure I got was about 200 amps.
I am going to open up the case now to have a quick look, I will be running back and forth. My hope is that it is something simple like capacitor shorted, but it easily could be worse (eg motor shorted).
i
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Get an electrician to check your shorts
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Noon-Air wrote:

Absolutely. 200 amps is a lot of punch.
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My shorts are pretty wet by now, from the rain and wet grass.
As far as the wiring, I would like to check out some things by myself (I am not a big stranger to electricity, built my phase converter blah blah).
i
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My shorts are pretty wet by now, from the rain and wet grass.
As far as the wiring, I would like to check out some things by myself (I am not a big stranger to electricity, built my phase converter blah blah).
i
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My shorts are pretty wet by now, from the rain and wet grass.
As far as the wiring, I would like to check out some things by myself (I am not a big stranger to electricity, built my phase converter blah blah).
i
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Have your buddy hold the breaker handle over for a while so the current can stabilize and you can get a better reading.
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Oscar_Lives wrote:

Funny, but OMFG
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I tried it, and I think that the breaker is good enough to reset despite that. In any case, it is kind of pointless, as I know that the current is too large and lasts too long.
I tried asking my wife to turn on the CB while I was outside, I heard some humming noise and then stop. I will wait a little until rain subsides and will go back.
i
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Turn up the "squelch" knob on the CB. That ought to stop the humming and noise.
10-4 good buddy!
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Sounds like you are not going to be helpful.
i
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You get what you pay for. Hire a tech and get it fixed. hang out on the world wide web and be entertained.
Cheap fuck.
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I am giving about 60% that I can diagnose it tonight.
i
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Ok, lets say that you *DO* figure out what the problem is... do you have the correct parts on your truck to actually make the repair?
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It depends. If it is a cap, I can buy one tomorrow. If it is the motor shorted, I will have to hire a pro.
i
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Please trim excess text. We don't need a Christmas Tree at this time of year.
--

Christopher A. Young
You can\'t shout down a troll.
  Click to see the full signature.
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On Thu, 03 Aug 2006 02:58:24 GMT, Ignoramus2645

I am an amateur, but...
At this stage I don't think you should be trying to measure amps, and since it is wet, I don't think you should be trying to measure volts.
You should turn off the breaker so that all hot leads to the compressor are disconnected, and when you verify that there is no voltage, you can start measuring ohmage, resistance btween the hot and hot, or the hot and the ground, in your compressor.
First realize that there are two power supplies to the compressor, a 110 volt circuit that uses the thermostat and the control board to control the contactor, probably the thing you heard humming below, and a 220 volt circuit that actually powers the compressor.
BOTH CBs should be off.
Everything below assumes that the problem is in the 220 volt circuit. If that's not true, post back.
If you got 200 amps, and even if you got less, but it kept tripping the breaker, it's pretty clear (though I supppose it's not entirely certain) that you have a short. An ohmmeter is the way to find it.
The capacitor could be the place, and that would be good I guess because they are cheap comparitively. IIUC, new caps have two caps in one can. One could be shorted while the other is fine. You shouldn't measure for a short until you meausure voltage between the common and each of the other leads. If the cap is bad, one might have voltage and the other might not. The voltage might be enough to burn out part of your ohmmeter. If the cap is still good, both halves might be hot. If the cap is hot, holding a charge, and has stayed hot while it was raining, it's probably good. But if you want to check more, if it does have voltage, you could apply a screwdriver with an insulated handle to the two connectors and watch for a spark. Then do it again and watch for a second spark. That should discharge the cap. Then you can measure the ohms and they should be verrrry low as current flows from your meter into the cap. With a small cap, the ohms would start to increase as the cap filled, but I reallly don't know how long that would take with one of these. This is much easier to see with an analog meter, a meter with a needle. The needle goes all the way to the right, and slowly back to the left. But like I saw with these caps with high capacitance (and 25 microf is a lot) I don't know how long this takes. I'd say if at the start each part of the cap shows substantail voltage, the cap is good.
It's not likely the contactor is shorted, and if it is, you should see sparking damage. If you want to check one more time, you can be looking at it when the 220 breaker is turned on one more time, and you can watch the contactor. If it trips but you don't see sparks there, that's not the problem.
I don't know if the outside fan is 110 or 220. I guess if it doesn't turn when the inside fan is turning, it's 220. That motor is a lot cheaper than a compressor. With my ac, you can take off the case, take off the fan blade, take off the plate, I guess it is a rain shield, and look for spark damage, and have someone look at that at the smae time yuou turn on the breaker, and see if that sparks, although maybe it sparks underneath where you can't see it.
Oh yeah, you should also measure the resistance of the two wires to the fan, and the two wires to the compressor. The compressor uses a lot of current so the resistance might be low normally. (I think it would present as higher to the AC house current than it does to the DC current from the battery in your ohmmeter.) I don't know what would be correct. Zero is too low.

This was worth doing. Is this the same CB that keeps tripping and where you measured 200 amps. I don't think so, but you didn't draw a distinction.

Oh, don't complain about Oscar's jokes. It was funny and beggars can't be choosers. :)

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The control voltage is 24VAC.

OK, thanks. I appreciate your tips, will try some of them for sure.
i
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On Thu, 03 Aug 2006 04:32:03 GMT, Ignoramus2645

Yeah I know, but I still think of it as 110 because that's what it is before it goes throught the transformer.
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wrote:

It's probably 5k "before it goes throught the transformer" for your home service. 8)
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