A/C worked 4 days ago, now wont turn on.

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Old 07-22-16, 03:53 PM
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A/C worked 4 days ago, now wont turn on.

Hey guys,

First post there and I do not know where else to turn. Quick background. I am at the tail end of a reno, and would like the AC to work before the hardwood comes Monday.

This past Tuesday the AC guy came and "fixed" (the issue was the wiring) on my thermostat and the AC was working. After it worked for an hour (I saw the AC unit fan spinning and felt cold air), I turned it off since no one would be there for 3-4 day.

Now...I try to turn it on and i cant! I noticed there was a lose wire (the black one that I think should go to socket "Y") Y is for AC right?

I tried everything, disconnecting the thermostat, circut breaker, the AC switch, the rain thingy plug near the AC unit. Dont know what else to do and the AC guy cannot come back until late next week!!

any other tips??? PLEASE!

Here are some pics or the wiring..is it correct?














 
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Old 07-22-16, 04:27 PM
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Do you have a multimeter? If so, set it to AC volts, set the thermostat to cool, and measure the voltage between the Y and C terminals at the furnace control board. You should measure ~24VAC. Likewise, you should also measure 24VAC between the G and C terminals. You likely will see two wires connecting to the Y terminal on the furnace control board. One of the wires should go to the thermostat and the other should go outside to the condenser/compressor (outside) unit.

If you don't have 24VAC at the Y & G terminals (referenced to C), check to see if you have 24VAC between the R and C terminals. If you don't, check for a blown fuse (you may or may not have one). If no fuse, then the 24VAC transformer may be bad.
 
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Old 07-22-16, 04:40 PM
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Thanks, I do not have a multimeter.

No other options?

Why would it work one day and not the other? Does my wiring look right?
 
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Old 07-22-16, 04:53 PM
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It's hard to tell from the pictures if the wiring is correct, but something doesn't seem right. For example, your thermostat shows a green wire connected to the G terminal. However, at the furnace control board, it appears that there is a white wire connected to the G terminal. I'm guessing that the thermostat wire may be spliced to another set of wires, because I don't see any green or blue wires at the furnace side, although they are at the thermostat.

When the thermostat calls for cooling what happens? Do either the outside unit or the blower turn on? If you set the fan switch to ON, does the blower come on?
 
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Old 07-22-16, 05:03 PM
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Yes, if I turn the fan to ON, it starts to blow air. When I turn it to Auto, and then cool, nothing happens.
 
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Old 07-22-16, 05:10 PM
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Can you try jumpering R to G and R to Y at the thermostat end? When you jumper R to G the blower should come on and when you jumper R to Y the outside unit should turn on.
 
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Old 07-22-16, 05:16 PM
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Sure, what do you mean by jumpering? Like switching R to G and R to Y?

So how would my colors look with my current set up?

BTW, thanks for the help so far.
 
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Old 07-22-16, 05:18 PM
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Carefully remove the red wire from the R terminal and touch it to the wire going to the Y or G terminal. Be careful that you don't touch anything else with the R wire, as it has 24VAC on it.
 
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Old 07-22-16, 05:24 PM
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ok, so like connect the red wire to the y terminal? So I would have essentially 2 wires connected right?
 
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Old 07-22-16, 05:26 PM
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That is correct. Alternatively, you could connect a jumper wire between the two terminals.
 
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Old 07-22-16, 05:36 PM
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ok, so once I do that (lets say without the jumper wire), the AC should work but the fan/blower alone wont work right?
 
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Old 07-22-16, 05:39 PM
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I would suggest that you try both individually (R to Y, R to G). If they both work, then you can try connecting all three wires together (R to G to Y). That will run the A/C normally, but of course it won't turn off until you undo the wires. If it does work with the wires jumpered, it means that the thermostat is bad.
 
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Old 07-22-16, 06:19 PM
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ok thanks.

I get how to connect R to Y and R to to test, but how would I go about connect all 3?
 
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Old 07-22-16, 06:52 PM
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Take the red wire out of the screw terminal at the thermostat and just touch it to the Y terminal. Nothing permanent. It may take up to five minutes for the compressor to start.

Since you said putting the switch to FAN ON works.... that means your green wire is ok.

If that is a battery type thermostat... .try replacing the batteries too.
 
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Old 07-23-16, 02:36 PM
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Hey guys...thanks to both of you. I connected the red wire to the Y. Now the Y houses both red and black wire...anddddd it turned on the AC asap!! Woohoo

House is slowly but surely cooling off...actually very slowly as its like 40 Celsius is Toronto today and I have no window coverings haha house was veryyyyy hot and humid.

Question....would leaving it like this cause any damage or something to work improperly, can I just leave it and continue using it as it??

Thanks again!
 
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Old 07-23-16, 03:26 PM
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How can you leave it like that ?
No thermostat ??? What will control the temperature ?

You either need new batteries or a new thermostat.

Your wire colors ARE NOT an industry standard so be very sure you label them with their connection letter.
 
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Old 07-23-16, 08:57 PM
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I don't get it ...but it working ? Why a new thermo?
 
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Old 07-23-16, 09:22 PM
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Are you pulling my leg.

If you short out two wires that the thermostat is supposed to control..... what do you think will happen ? With those two wires shorted.... the compressor will NEVER shut off.
 
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Old 07-24-16, 04:14 AM
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Haha got it. Thanks!

My bad
 
  #20  
Old 07-24-16, 04:22 AM
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Glad to hear that the A/C works by connecting the 3 wires, and thanks for taking over Pete. I was gone all day yesterday, so I didn't have a chance to check back. As Pete mentioned, if everything works okay with the R,G, & Y wires connected, then the problem is your thermostat. It's either defective or the batteries need replacing.
 
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Old 07-24-16, 10:47 AM
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Hey Pj,

So if the thermostat is good, then connecting the red back to the R terminal should work with a new thermostat right?

I also have a new Ecobee3 thermostat I am looking to install, based on what you know and my wire set up below, how would I connect all the wires and colors to the ecobee terminals?
 
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