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-   -   A/C compressor not kicking on, not cold! (

onecrazyfoo4u 07-07-2009 11:48 AM

A/C compressor not kicking on, not cold!
We're in the socal desert, so it easily gets up to 115 during the summer. We bought the house about a year ago, it was built in 05, and only lived in for a few the air conditioning hasn't had much more than a year of use. House is single story stucco with 1600 sq. ft. It's a goodman air conditioner, as well as goodman furnace/ evaporator in the attic. I can provide pictures and info on both units if needed.

It just started happening this past month. We keep our thermostat around 80-82 usually. When it turns on the attic fan and condensor fan both turn on. Sometimes you can hear the buzzing of the A/C compressor kick on, sometimes not, it's about 50/50. Obviously it's not blowing cold air when the compressor doesn't kick on, just recirculating inside air. Both fans kick on every time. When just the fan kicks on, it can take almost an hour before the compressor kicks on, sometimes less, it's just random. What would cause the compressor to only come on half the time? I've heard it could either be a compressor problem, or capacitor problem, is that correct?

I've done all the obvious maintanence, like replacing filter monthly, checked all circuits, fuses, just cleaned the condensor coils and straightened all the fins a week ago. No leaks, the bigger pipe does get cold, but not icy/frosty cold like I remembered it being last season. Evaporator in the attic...I can't figure out how to get to that thing, looks really complicated. Anything else I should check that I'm missing?

Let me know the steps I should check to get it fixed, it sucks only having air conditioning half the time! Thanks so much for the help!

handyguys 07-08-2009 09:04 AM

I think you have likely already checked the obvious stuff, might be time to call in a goodman service tech. You can check this podcast out to see if you missed anything obvious.
Episode #69 - Air-conditioning Troubleshooting checklist

onecrazyfoo4u 07-08-2009 12:27 PM

Thanks for the link. I'm just trying to narrow down what to look at and check. Would the problem most likely be the compressor motor itself, the capacitor, low freon, or could it be the thermostat?

A link or knowledge to common symptoms of each one going out would be awesome, I can't really find it. What would cause the compressor and cold air to work only half the time? Thanks allot!

handyguys 07-08-2009 12:38 PM

I'm no expert, thats why I interviewed an expert for the show in the above link. That said. I think common sense would rule out low freon if it does cool sometimes. It might also rule out the motor. So, my non-expert gut would tell me it could be a capacitor, the thermostat, a control board or a loose electrical connection.

onecrazyfoo4u 07-09-2009 05:54 PM

4 Attachment(s)
Okay well here's some pictures of my system. There were no loose wires or bad connections from visual inspection. The capacitor still looks brand new. I'm at a loss here....the only other thing that could be wrong would be low fluid level or a bad compressor correct?

First picture is the data about my outside A/C unit. Second is the label on the compressor. Third is the label on the fan. And the last one shows all the wiring connections and my capacitor, it all still looks brand new. Anything look wrong or connected wrong to you guys? What else can I check? Thanks in advance!

kok328 07-10-2009 01:41 PM

How do the contacts look on the contactor?
Look for signs of burn, pitting or just plain gone.
Basically, you have 220VAC coming in and the T-stat wires activate the 24 VAC coil and pull the contacts in. If the contactor is worn out, then no power will be leaving the contactor to control the compressor and fan motor. Depending on how the contacts land, it could cause intermittent problems.

onecrazyfoo4u 07-10-2009 03:46 PM

Is the contactor the big black box in the last picture with all the terminals, that has like 6 or 7 wires connected to it? I tightened all the wires, there was only 1 or 2 that were a little loose. I didn't see any signs of burning, and I don't know what pitting means?

I know that the thermostat wires are the 2 on the far right, where the gray incoming wire connects to the 2 purple wires. Should I just go through each connection and undo it and reconnect them? Would I be better of soldering the incoming thermostat wires to the 2 purple wires on the right?

It's just weird how it works about half the time. The other 50% of the time, the fans will kick on right away, and you have to wait almost 30 minutes before the actual compressor kicks on. Thank you so much for the help!

kok328 07-10-2009 05:22 PM

yep, the black box is the contactor. also check for good connections under and blue wire nuts. soldering shouldn't be necessary. pitting - the contacts on the contactor should be smooth, pitting will make it look round and possibly corroded. These contacts over time will burn/rot away and the contactor will not transfer power when the coil is engaged.
If you have a volt meter, let me know and we can check a few preliminary things that may exclude others. We will first start by checking to see if you have 24VAC to the contactor coil. The results of this check will determine what we need to check next. If you'd like to just change the contactor, the are only a couple of bucks but, make sure you get one of the same amp ratings and pay attention to where the wires come off so you dont' get them mixed up. Do you have any wet spot on the condensor coils that won't dry regardless of anything? This would be the oil residue from a freon leak. They typically will occur at the ends of the tubes (kinda like a radiator on a car).
If the condensor fan comes on w/out the compressor, it's may be a bad compressor.

onecrazyfoo4u 07-10-2009 10:31 PM

Cool, thanks for the help. I'll go recheck all the connections hopefully tomorrow, and probably just redo them all. Yeah, I have a voltmeter, please just let me know what connections to check and where they are.

There's no wet spots or signs of a leak anywhere. But it said it was last filled in 05, so maybe after 4 years (even though it's only been used for 1) you need to get the coolant topped off again? Yeah, the condensor fan comes on every time, just the compressor doesn't kick on all the time. It seems to kick on all the time when it's cooler out, or at night. Just during the hottest part of the day that it doesn't want to kick on. Thanks.

kok328 07-11-2009 06:00 AM

If the fan comes on everytime but not the compressor, then we should check the wires that leave the contactor and lead to the compressor and we won't have to work backwards from there. There should be a cover box on the compressor where the wires enter the compressor. Remove the cover and check the connections for corrosion and/or burns. Repair as necessary.
Also, does the casing on the compressor feel hot when this condition occurs?

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