Not getting 220v at either wire in quick disconnect


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Old 08-04-08, 09:32 AM
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Not getting 220v at either wire in quick disconnect

Here goes, i've been looking around the internet for days... living w/out A/C for over a week, and can't find anyone who has the same problem i have. So, i've decided to make a new post.

I have an outdoor a/c unit w/ an unfused(from what i can tell just off and on) quick disconnect outside. I'm not getting any voltage to either red or black wires and ground appears to follow the correct path. I'm getting 24v at the contactor point from t-stat telling me the unit has input from there. But (obviously) no 220at any leg of the contactor. My heater and interior blower works fine just outdoor unit won't cool the air coming through the ducts. I don't have a designated circuit in my breaker box for just the outdoor unit(from what i can tell i only have the one for the heater and a/c together). Also if someone does help me figure this thing out, i think i have to wait for 3 hrs. before turning on the a/c so that the cap will recharge, correct? I'm sorry if it sounds like i'm rambling ..... but i am stubborn and hate asking for help, but i hate very much more hearing my wife gripe about being hot any help is appreaciated...
 
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Old 08-04-08, 09:53 AM
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Are your voltmeter prongs long enough to able to make contact at those possibly recessed female terminals of the disconnect? It just seems odd that you have furnace function, indicating the breaker is good, yet have BOTH legs of power out at the disconnect, rather than just ONE leg out.

Make sure your probes are making contact, then get back with us. I know with dryer and range recepticles, I often do not get a reading because my probes cannot get to the bottom in the female slots to make contact. So please check that out.

To try to further advise without knowing this would be a waste of time
 
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Old 08-04-08, 10:20 AM
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ecman, first of all thank you very much for the quick response. yes the probes are long enough to reach the terminals, but just in case i was mistaken, i stripped back part of both lines (w/ power off of course) from the input side of the disconnect (made sure i had clearance and turned power back on) and tested in the line itself and am still getting no voltage. doing a resistance test across the lines (1 probe on black 1 probe on red w/ power off) i get an infinite amount of resistance (i.e. the meter will not zero it just reads 1. don't exactly know if that was the right way to test it but thought i'd give it a shot.) thanks.
 
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Old 08-04-08, 10:36 AM
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is your furnace breaker a 230 volt type double wide?....I've seen many panels mislabled by previous home owners. The outdoor unit will be double wide. I'd go through the panel resetting every double breaker and test further with the a/c off. Then I'd go recheck voltages coming into the contactor. I had an old house a while back that had 2 breaker panels and still couldn't find the breaker. Turned out they added another panel out at the alley at the pole and voila. Just keep in mind if it's a tripped breaker, there is a reason that it tripped.
 
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Old 08-04-08, 10:38 AM
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You said that you have a quick disconnect box, I presume outside by the unit.
It sounds as if you are measuring the black to ground and then the red to ground. and getting nothing.
Dumb question, are you measuring from the black to the red wire? Secondly, when you pull the disconnect and take your reading, are you going to the black and red wires at the top of the disconnect that come down to the switch or to the bottom power wires?
The 24v that you are reading is probably coming from the air handler, which should be on a separate breaker from the outside unit. Tom
 
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Old 08-04-08, 11:28 AM
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tinmantu, the only double wide i've got is to the dishwasher the furnace is a single....hmmm.. maybe another breaker box in the house i can't find, and yes i'm well aware if it's popped there's a reason for it... i'm hoping it was just because of a power outage we had here about the same time the a/c went out, if not i'm sure i'll find out real quick that it's not ...

gardener, yes the quick disconnect is outside near the unit, yes black to ground,(actually to test if it was my ground i put the meter probe directly in the dirt as well and still was able to read 24v to the input of the contactor from the t-stat but nothing at the disconnect) red to ground, and across both red to black nothing. tested my meter by putting ends in an outlet, and it read a perfect 120.....and i'm reading at the disconnect from where the wires input to the disconnect from the home, not the wires that lead down to the outside unit... and trust me no dumb questions at all, lol... knowing me.. it's me that's making some dumb mistake. i crawled under the home and didn't find any breaks from the disconnect to where they lead up into the wall (after removing the pvc)... where they head from there i have no idea... tugged the wires slightly they didn't feel loose so i assume there's no breakes there.... i'm stumped.
 
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Old 08-04-08, 11:39 AM
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gardener, you say the ouside unit should have it's own breaker?.... hmmm.. there's definitely something i'm missing then because the only breaker i have is for the furnace itself, and yes you were correct the 24v is coming from the air handler telling the contactor to.... contact lol... not the t-stat directly. thanks to you both tinman and gardener for the quick replies.
 
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Old 08-04-08, 11:39 AM
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If you've been under the house, try tracing the high voltage to the a/c back to it's origin. Might lead to another panel...just a thought.
 
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Old 08-04-08, 12:00 PM
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EUREKA!!!... i found my double wide circuit.. tripped and screwed into the concrete wall behind my disconnect....i'm quite positive that IS NOT up to code so my next order of business is to rewire that whole damn thing.... i'm just amazed that i could spend 200 bucks for a home inspector to come out and DO HIS JOB before i bought the home only to find things like this after purchase... ah well... i guess i'm not perfect at my job either so i can't necessarily get mad at him for one mistake. Glad i just found it before it caused some serious damage... though it makes me question what else was wired in improperly. Second order of business though since the capacitor has been w/out constant power for over a week i should let the system be for about 3 hours before i run it correct?... or is that only necessary for new capacitors? Thanks to all for your quick responses... it's good to see that there's people out there who actually take a little time to help when other's are in need.
 
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Old 08-04-08, 12:06 PM
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It's not necessary for capacitors....it is necessary for a compressor with a crankcase heater to sit for 24 hrs before startup. If your weather has been as hot as you describe, I wouldn't be worried about any waiting period...get it repaired and get mama happy.
 
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Old 08-04-08, 12:07 PM
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The furnace breaker you speak of. Is it a double? If so, what amp is it.
Go back to the outside knife switch at the unit. Look at the blac, red and white wires. Are they in a jacket? In other words three conductor NM sheath cable?
Now with what you see there, go to the breaker panel and take the cover off. Do you see where those same wires that you just looked at come into the breaker panel in the home?
Should be yes. If so what do they connect to? Tell us what you see and lets go from there.
What size breaker panel is in the home? 100 amps or more? In older homes, some installers will pick up a feed from the breaker panel bus and install another panel near by, maybe inside or out side of the dwelling. If it is possible to trace these wires, you will come to your open circuit.
As another poster said earlier, he found a sub panel outside in the alley and Shazam he was back in business. LOL Tom
 
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Old 08-04-08, 12:08 PM
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3 hrs for the cap isn't necessary. I think yer confusing it with something else, maybe transporting refrigerators on their sides?
 
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Old 08-04-08, 12:12 PM
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Eureka, You did it BUILD A FIRE IN THE HOLE!!!!!!!!!! Tom
 
 

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