Air Conditioning - Contactor? Capacitor? Compressor motor?

So, I'm trying to start with the easy stuff here. For three years now, my A/C has stopped working once each year. First it was the low voltage transformer, then the fan motor and now the outside compressor and fan are not coming on.

The low voltage transformer is good. (tested)

When I push the contactor button, nothing happens.

Related to the contactor, twice I've noticed (in turning power off, trying something and turning power back on) that sometimes when I go to check the outside compressor/fan, the button on the contactor will be pushed in and the contactor will be humming. When power is cut, it pops back out and then when power is restored, it will not go on again.

The capacitor outside looks great, no leaks, it's not bulging or anything.

I haven't tried to turn the fan manually yet, that will be next.

I went to the local electrical supply shop and bought another contactor to replace it as it's a common issue for that to be the problem. But, I'm an idiot and moron and got a two pole contactor instead of a single pole contactor. The shop will not do returns on electrical supplies, even if it's obvious it wasn't installed or attempted to be installed. My question here is whether or not I can adapt the two pole contactor for my use or if I must have a single pole contactor.

Aside from that, what do you think (knowing of course that you can't be here to see it) would be the most likely problem? While waiting for an answer, I'm going to try the fan blades and see if they turn freely or not.

Thanks for any help.

The fan blades will turn manually very easily.

Sooo... I'm kind of leaning towards the contactor as power goes through it for both the fan and the compressor and neither is coming on. If replacing that doesn't work, I'll try the capacitor and if that doesn't work, I'll call a professional.

Wish me luck.:p

Well... it wasn't the contactor. So, the capacitor will be next, but they didn't have one locally. I'll have to try Savannah tomorrow. :wall:

There is no rating on the capacitor I pulled off the outside unit. Is there a way to tell what it is supposed to be, or will it really matter? The only thing about the capacitor I could find on the schematic for the unit is that it is a "Dual Capacitor".

When I push the contactor button, nothing happens.

But, I'm an idiot and moron

got a two pole contactor instead of a single pole contactor.

Push in contactor, nothing happens. Major clue there maybe no 220 at the contactor to make anything run. You found you have 24 volts control power. How about checking line voltage to the unit?

Usually the single pole contactor is used to be cheap and to run a crankcase heater in the compressor. Just make sure the CCH always has power and connect everything else the same.

Model and serial number of unit?

There was main power going into the contactor. After replacing it, I didn't check again though.

So... I went out and checked again. No power. Checked connections. Checked all three breakers... outside breaker was now tripped. Reset. Lots of humming, but no activity. There is now power on the other side of the contactor though... there is also power in and out of the capacitor.

Rechecked wiring again just to be sure I had my connections right and could smell burning from the compressor.

So, either I had two problems or I did something to fry the compressor. Kinda 50/50 chance there. Anyway... power has been cut again, no more burning smell. I"ll look into a compressor in the morning.

I'll also get the model and serial number of the unit in the morning when it's light out so you can shed any insight on anything I may have missed.

Oh yeah....

I'm an idiot and moron

Dee da dee... told ya. :o

There are several model and serial numbers on the different components of the system. I can't find anything that says, "Hey, the unit is this brand and model".

The outside unit says Intertherm on the front of it and the compressor says Copeland. The compressor model number is CR42K6-PFV-220 and the serial number is 9F14973H, the compressor code is T5A.

The indoor unit says Coleman Evcon on the door. The coil says Nordyne. The model number for the indoor unit is EB15B and the serial number was 960545211.

Anyway... the capacitor isn't swollen or out of shape, no leaks. So, I'm thinking that may not be the problem? I double checked my wiring to what it was orininally. Everything is correct. But, now there is that electrical burning smell from the compressor and the outside breaker trips. Neither the fan nor the compressor turn on.... :wall:

Okay... sorry for such a long thread....

Went over everything with a fresh look for the new day.

Inside, everything works and checks out.

The outside fan/compressor won't run.

The contactor receives the 24 volt signal to turn on.

The contactor is receiving 220 from the outside breaker box. Both sides on the top have 110, even when the contactor is not engaged. When the contactor engages, the breaker trips.

There are no bare wires, nothing is touching, the system is grounded.

I would think that if the contactor is not engaged, there should not be power on the other side of it.. right or wrong?

This is reproduceable with the old contactor as well, so it's not an issue with the new contactor.

Thoughts, suggestions, remind me that I'm an idiot and moron again? :p

I had a repair service come out and look at the unit. It is the compressor shorting out. They said it needed to be replaced. Replacement of the compressor w/ labor comes to $950 and a new unit w/ installation is only $1800. :eek:

Looks like my electric bill will go way down for a few months, it's gonna be a hot summer. :mad:

This thread can be closed unless anyone has any suggestions or cheaper alternatives.

I'd suggest at least getting one more opinion and bid from one other company....did you see them checking the actual pins from the compressor to ground?...not saying they are lying, just wondering if you observed them testing.

Agree, $950 is high for a comp while $1800 is low for a new unit. Another opinion is prudent.

I watched them check everything.... And the $1800 for the new unit is just for an outside unit. Nothing inside would be changed. I don't know if that makes it more or less reasonable of a price.

They estimated the compressor (before calling to see about the price) at $400-$500. Assuming it is $500 or thereabouts, is $450 in labor for a compessor change about normal? I've never had to deal with it before.

I called the supply shop that I got the contactor from and they couldn't find this compressor model. I told them I was looking for a ballpark price to make sure I'm not getting screwed (without telling them the estimate from the hvac repair company). They gave an estimate of the same based on the information I gave them about my system.

I probably will call another company though, just to check. Just for the record though, anything and everything in this area has always been overpriced, from groceries to real estate.

If you buy new, I would think that if you have an older system, the indoor coil should be replaced also....especially if there has been a short to ground. Line set may also need to be changed out to protect your investment in the new system..a reputable company will see what you have and what you need...use the money from the electricity you are saving from going without and at least do some checking around, IMO.

According to Copeland that 42000 BTU compressor is available to all US customers. Meaning it is still being produced.

$450 for labor is actually pretty good. It takes a while to change a compressor.

In your case, all the refrigerant has to be removed.
The top of the unit needs to be removed.
Naturally, the old compressor needs to be removed. WHILE bleeding nitrogen through the system!
The liquid drier needs to be removed.
The new compresor needs to be set in place.
A high acid suction line drier needs to be cut in.

Again while bleeding nitrogen through the system, the new comp, liqid and suction driers need to be brazed in.

THe system then need to be pressure tested with nitrogen and all new jionts tested for leaks.

The system should hole about 250# of nitrogen pressure for 20 min or so. Good time to take lunch.
Satisfied with the pressure test. You now do a vacuum test.
The system is placed on a vacuum pump and evacuated to 500 microns or lower. It now needs to hold 500 microns with no apreciable rise in 15 min or so.

Now the system would be ready to be recharged. You start with the manufactures charge listed on the unit name plate. Start it up and make charge adjustments as needed.

Those are the steps taken, sometimes goes quickly, sometimes not. It's anywhere from a 1/2 to a whole day job. And not fun in hot weather.

Changing the entire outdoor unit and the inddor coil is much easier. Changing these to a higher seer would ultimatly save on elec, but to get the full benifit you would need a variable speed blower.

Guess it's time to look at that checkbook a little closer.

Thanks for the info guys. Yeah, I figured it would be a while because of charging an adjusting, but I didn' know about the other stuff.

There's nothing to look at in the checkbook. This is just going to be a hot month in my house. I figure I'll be able to have it done sometime in the middle of next month, which is still hot around here.

I really do appreciate all your help and information. Thanks again.

Now imagine hauling all that stuff to the roof of a 3 story building, it only gets worse.

Keep us posted.