Funny how the AC always breaks in summer

Chevello · Jun 21, 2015

It could be worse, it could be the middle of July or August, but it's bad enough.

Friday I walked in the house and ew, muggy and yucky. Went out and the condenser unit wasn't running. Opened up the access panel and found that the cap had one of the wires melted off. It was 6.30PM on Friday, HD Lowes, sears, grainger all came up empty for the part before next wednesday, so I ordered a new cap from Amazon. It came in yesterday, I installed it and reset the breaker. The condensing unit now comes on as far as the condenser fan, but the compressor? No love.

When I first reset the breaker, the electrical box made a sort of stuttering noise, and the condenser fan ran like at half speed before it tripped the breaker again, but it didn't do it when I reset again. It did run the condenser fan slow once when I shut the unit off from the thermostat, but I just flipped off the breaker again out of annoyance, put the covers all back on and gave up for the night. It's not a two speed fan on the condenser, and with a screwdriver stethoscope I could hear an intermittent hum (every couple of minutes or so) from the compressor like it was trying to start but couldn't.

So, the AC guy is coming Monday. Hopefully.

Any trouble shooting steps I missed that you HVAC guys would have taken? Maybe I got a bad replacement cap?I was thinking I could check to see if the contactor was not making full contact, which would explain the fan running half speed if only one side was working intermittently, but when it's running full on, the compressor still doesn't come on.

It's about a 10 year old Goodman. Already had to replace the cap twice and the condenser fan once.

Worst case, is this going to be a $100 $500 or $1000 repair if it needs the compressor replaced?

Dean · Jun 21, 2015

Run capacitor or start capacitor?
You sure you got it hooked up right?
Got an AC volt meter?

It's not worth replacing the compressor if it's bad, replace the unit.

Chevello · Jun 21, 2015

Yes I have a voltmeter.

Not sure if it's start or run. When I replaced the condenser fan motor, it came with a cap, so I left that side off the dual cap already in the unit and used the cap that came with the motor.

The one that melted is the dual cap that was replaced (twice) already. The wire that melted off was the one on the "herm" terminal. The two wires on the C terminal were OK.

Dean · Jun 21, 2015

OK, a metal run capacitor then, not a plastic start capacitor.
I'm betting the there is now a mistake in the capacitor wiring to the compressor side.

Trace the wires, there has to be one on one side of the capacitor going to "Run" terminal of the compressor and one on the other side of the capacitor going to the "Start" terminal of the compressor.
Naturally there also has to be 240 volts connected to "run" and "common" when the contactor is pulled in.

jpete · Jun 21, 2015

Pull the plug at the compressor and take 3 ohm readings.
A-B, A-C and B-C (common, start and run terminals) and 2 of the readings should add up to the third(highest) reading.

Also check all terminals for continuity to ground.

If the compressor isn't mechnically dead, you might get another season or three out of it by adding a "hard start" capacitor in addition to the one already there.

ZZ69chevelle · Jun 21, 2015

Chevello said:
...It's about a 10 year old Goodman...

There's your problem right there. They aren't known for quality to put it kindly. I wouldn't put too much money into fixing it if you can avoid it. :thumbsup:

Chevello · Jun 21, 2015

Thanks guys. The kids are taking me to the movies right now, so I'll fool with it when I get back.

Hopefully the AC at the theater works. Man, it's muggy

shovelrick · Jun 21, 2015

Try a hard start, if its not tripping the breaker as soon as you reset it a hard start should get it working but keep in mind its on its way out. The hard start will come with a wiring diagram, should be under $20 and I would waste $ on a potential relay hard start.

Chevello · Jun 21, 2015

Dean said:
OK, a metal run capacitor then, not a plastic start capacitor.
I'm betting the there is now a mistake in the capacitor wiring to the compressor side.

Trace the wires, there has to be one on one side of the capacitor going to "Run" terminal of the compressor and one on the other side of the capacitor going to the "Start" terminal of the compressor.
Naturally there also has to be 240 volts connected to "run" and "common" when the contactor is pulled in.

Wiring is confirmed, took a photo of where the wires all went before I replaced the cap. Wire from Start on compressor to Herm on Cap, wire from wherever else on compressor to C on cap.

Second wire on C on cap goes to condenser fan.

Went out and turned the breaker back on, and the thing (condenser fan) fired up at half speed again. Almost seems like a smallblock with a miss.

Note that the thermostat is set to OFF not COOL, so there is 0V on the coil of the contactor.

I have 246VAC at the line side of the disconnect with the disconnect pulled, 246vac at the load side with it in, 246vac at the line side of the contactor and 158VAC at the load side of the contactor.

jpete said:
Pull the plug at the compressor and take 3 ohm readings.
A-B, A-C and B-C (common, start and run terminals) and 2 of the readings should add up to the third(highest) reading.

Also check all terminals for continuity to ground.

If the compressor isn't mechanically dead, you might get another season or three out of it by adding a "hard start" capacitor in addition to the one already there.

Thanks. If I decide to pull the top of the unit, I'll check that. Not sure if I want to get that far into it when the AC guy is coming Monday.

ZZ69chevelle said:
There's your problem right there. They aren't known for quality to put it kindly. I wouldn't put too much money into fixing it if you can avoid it. :thumbsup:

Yeah, I suspect that it was the cheapest unit available that juuuust barely met the cooling requirements of the house. Before the skylights and windows on the South side were added. It tends to come on some time in June and if I'm weather lucky it shuts down before Halloween.

It's a rental, so the landlord is more likely to dump money into this one if it's a buck cheaper than a new unit. He's a good guy and we get along, so I like to fix things when I can to save him a bit.

shovelrick said:
Try a hard start, if its not tripping the breaker as soon as you reset it a hard start should get it working but keep in mind its on its way out. The hard start will come with a wiring diagram, should be under $20 and I would waste $ on a potential relay hard start.

Yeah, we'll see if the AC guy puts one of those in. I don't know what it is, but I think I'm to the point of "I gave it the old college try, so time to call in the Pro team."

Thanks for the help guys.

Gary S · Jun 21, 2015

It can't break in the winter because you aren't using it.

Dean · Jun 21, 2015

If it needs a hard start kit the symptoms would be - Compressor will hum and try to start then shut down on its thermal over load.
Do you hear it doing that?

Chevello · Jun 21, 2015

Dean said:
If it needs a hard start kit the symptoms would be - Compressor will hum and try to start then shut down on its thermal over load.
Do you hear it doing that?

No, it just hums for a second and then it remembers the words.

Oh, I mean it hums for a second, maybe not even that long then gives up. I can't imagine it's going into thermal overload that quickly. But what do I know, that could be it.

Chevello · Jun 21, 2015

Gary S said:
It can't break in the winter because you aren't using it.

That's the joke

Sid Coleman · Jun 22, 2015

I was trying not to say what Gary did

i feel your pain, happened to me a few years ago. Doncha just love this 90+ temps :/

Hope they fix it quick!

jpete · Jun 22, 2015

Gary S said:
It can't break in the winter because you aren't using it.

The A/C I don't have never gives me problems.

FLASHED · Jun 22, 2015

I had to replace one of my window units today in our bedroom ,I like it COLD and the old one just could not keep up .

AJS · Jun 22, 2015

On the compressor: C (common) goes to line1 on the contactor. S (start) goes to the HERM terminal. R(run) goes to the other side of the capacitor ( or the C terminal if you got a dual run cap) and from this terminal a wire should be ran to line 2 ( the other side of the contactor).

jfkheat · Jun 22, 2015

The compressor went out in my unit a few weeks ago. I'm out of town working so I haven't had it fixed yet. I can only imagine what it is like inside my house now. January 2014 my blower motor quit. I didn't have time to get it fixed before I had to go out of town for work. When I got back home a couple weeks later it was 34 degrees inside my house. Everything in my refrigerator was froze solid.
James

Chevello · Jun 22, 2015

I just popped the wires off the old cap one at a time and stuck then on the new one confirming the correct terminals as I did, so the wiring should be fine. (Although, how many of us have got plug wires wrong over the years, shouting "They can't be wrong I only had one off at a time!! Then only to find out 5 and 7 were swapped

)

AC guy is coming this afternoon, so hopefully he can just do some sort of AC guy thing and sort it out.

I added a window unit to the garage last weekend so it's now the coolest room in the house. I mean temperature wise. It was already the COOLEST room in the house.

When Sandy rolled through and our power was out for a few days, I had a generator to keep the fridge and tv on, but the temp in the house only got down to about 50 before we got power back. That was as close as we got to frozen inside. Another 10 degrees and I was going to start worrying about the pipes. At least that isn't a problem with this.

Chevello · Jun 23, 2015

Compressor is seized. AC guy said it was trying to draw 55A on startup. Apparently it's common on Goodman units. Then he looked at the air handler and went "Whoa, yeah, that's pretty ancient." Soooooooo, now we have to wait. His boss has to call my landlord, yadda yadda at least two weeks before they can get to me anyways even if the landlord says "Go" tomorrow.

Managed to fit window units that I had leftover from the old house (one of which was in a window in the garage making it comfy out there for working on the car) into the only two windows where they will fit, and trying to blow cool from the bedrooms into the rest of the house. Somehow I doubt a 10K BTU and a 5K BTU are going to cover a house that the 3 tonner was overworked trying to cool. But at least the bedrooms are reasonable.

Must have sucked living in this crap back in the 50s and 60s before AC became fairly common. Especially for my wife whose medications make it extra difficult for her to deal with. That's my biggest concern. She'll be hibernating in the bedroom until it's fixed I think

Funny how the AC always breaks in summer

Chevello

Dean

Chevello

Dean

jpete

ZZ69chevelle

Chevello

shovelrick

Chevello

Gary S

Dean

Chevello

Chevello

Sid Coleman

jpete

FLASHED

AJS

jfkheat

Chevello

Chevello

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