My A/C Unit is Bipolar

Old 08-04-15, 07:05 AM
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Angry My A/C Unit is Bipolar

I could sit and ramble on, and I probably will. I guess the tl;dr version of this post will be my A/C unit wasn't working at all, when my house was 82 degrees and I couldn't sleep a drop because of it, but now it's running at 9:37 AM and the rest of the house is about to wake up... great.

Now, before I get yelled at for posting a thread on a solved problem... or semi-solved anyways, I just want to make something clear. It was NOT working at all last night. :NO NO NO:

At about 11:00 PM, my air kicked off, as usual, and I thought nothing of it. I usually keep my A/C on 72, so that's fine. Nice chilly house. Time for bed. Imagine my shock when at 12:30 AM (just 90 minutes later) it was 82 degrees! I was sweating like I ran a marathon, and my A/C was not there to be the hero.

After trying everything I could for probably 35 minutes on the thermostat, I gave up and tried to go to bed. I say tried because I haven't yet.

At about 2:15, I noticed that air was coming through the vents, but it wasn't air from the great white north. It was your average, cool enough to make you forget it's 82 in your house but not cool enough to allow you to sleep. It never dropped below 79.

After hours of online FAQs and what not, I determined at around 5:15 this morning that it was just the fan in the house running and that the actual A/C was not on. I live in the mountains of Western VA. I'm not going outside to check at 5:15... there are bears out there!

But my dogs came calling at about 8:20, so I took them outside. I decided to have a look-see at my unit. (And my apologies for my lack of knowledge on the matter, but my unit is a Nordyne one. That's all I can say because whoever installed it was supposed to write the M/N and the S/N in the spaces provided and didn't.) It was not on. Like all power had been cut to it. Irrelevent to the story but my dogs were severely annoyed with this stray dog that came into my yard to visit, strange that it decided to do it on arguably my roughest start to the day in the last 10 years or so.

After the stray went astray and my dogs went inside, I noticed a click coming from the unit. It was a faint but audible click. It did so probably 3-4 times. Then there was this very loud click followed by the fan beginning to power on. When I thought the heavens would smile on me, the fan stopped. Turns out that moment that felt like an eternity was one second. It literally started to turn on then shut down in one second.

Well I was stumbling around in my yard, talking to myself, browsing numerous FAQs, throwing "gestures" in frustration, must've been a spectacle to watch becuase my neighbors decided to bypass the morning coffee and watch me...

So at that instant, I realized I'd get farther with the model number and serial number (M/N and S/N above). Turns out, the magic ticket was my lack of being able to fit in tight spaces, a talent I was great at 15-20 years ago, but not so much now. Either that, or I just got momentarily tired and the top of my unit looked like a good place to catch a few Z's. Either way, I was laid on top of it looking for the numbers, and it jolted, which made me fall. Thankfully, the neighbors had gotten bored of me at that point. Anyways, the fan kicked on, and I got a euphoria when it stayed on.

I come inside though, and it still hadn't flipped the switch yet, metaphorically speaking. My A/C has been on "Cool, Auto, 73" all night. So I found this great website, and as I started to type, I got chills. No it wasn't the lukewarm air hitting the sweat on my back and chilling me. No it was actually cooling down! And as of 9:55 AM, it is now 75 in my abode!!!

In 18 minutes, the temp has dropped 5 degrees in my house, which is awesome. Good timing too, because it's supposed to be 91 where I live today, it's 77 right now, and the heat index is expected to be in the upper 90s. Granted that's not Southwestern US hot, but around here, in the mountains of Western VA, 85 degrees is torture. Not because we're not used to it here (it can get as hot as 100+ and had numerous times in the last few years, apart from the unusally cool summers of the last 3 years including this one). The humidity is always at 90%+, so an 80 degree day feels like a 90 degree day.

Anways, once again tl;dr, my A/C unit didn't work, but now works. I guess my question would be, if anyone has any flipping idea, what the problem is or might be? This happened about three nights ago too, but wasn't as profound. And the unit seems to work during the day, but it makes sleeping next to impossible when it decides not to work at night, which makes for a brutal day. GI2

If nobody can answer my question, then use this as an answer. If all else fails, lay on your A/C unit! (Seriously don't, it is dangerous. I fell when I did so.) And even if this thread ends up garnering no response in any way, I hope you enjoy my stressful morning, my rambling, my incorperation of jokes/sarcasm/making fun of myself. It's the Southerner in me I guess.

And all that said, I'll try and get some sleep now. Once again, thanks for allowing me to take up a post with whatever the above just was. Any help/advice will be appreciated. And do not say new neighbors because they decided to enjoy my ordeal... I've known I've needed new neighbors from the beginning. And if my neighbors are reading this, I've always loved you!

Have a great day everyone, and if I have any further problems, I'll definitely come back. This site looks helpful and actually doesn't cost me $68 to talk to a representative, so there's that. Thanks again!

Old 08-04-15, 07:34 AM
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To troubleshoot the outside unit (compressor, condenser and condenser fan), you'll need to wait until it stops working again. If you have a voltmeter (or are willing to buy one), there are several voltage readings that you can take that will help us isolate your problem. You'll need to remove the cover(s) from your outside unit so you can get to the electrical components inside the unit.

When the outside unit isn't working (thermostat calling for cooling but outside unit not running), turn off the power to the outside unit (there should be an electrical disconnect near the unit). With the side cover(s) removed, look for where the wires come into the unit. You'll see some heavy wires (240VAC) and a much smaller diameter cable carrying the control signal (24VAC). The control signal wires will be connected to the internal wiring using wire nuts. With your voltmeter set to AC volts, check to see if you have ~24VAC at the control signal wires (wire nuts).

When the thermostat calls for cooling, it closes 2 relays inside the thermostat: one sends 24VAC to the air handler (G terminal) to turn the blower on, the other sends 24VAC to the outside unit (Y terminal). The 24VAC control voltage at the outside unit energizes the contactor, which is really just a relay. When the contactor is energized, it pulls down the contacts, closing the circuit and and sending 240VAC to the "guts" of the outside unit.

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