ac not working don't have 24 volts


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Old 08-12-09, 04:21 PM
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ac not working don't have 24 volts

Hello, I am having trouble with my ac. The original problem was that the inside fan would come on but the outside compressor and fan would not. I pushed the manual button on the contactor and that kicked on the fan and compressor. So i figured i had a bad contactor and replaced it. Then when i turned on the ac nothing came on. I pushed the manual button on the contactor and the outside fan and compressor come on. I am not getting 24 volts at the outside unit itself or at the transformer located inside the furnace when i put the thermostat to cool. Now i am thinking the transformer blew?? Any suggestions will be greatly appreciated. Thanks
 
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Old 08-12-09, 04:29 PM
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You have miswired the new contactor causing a short in the low voltage. If you could post some pics of the contactor it would help greatly.
 
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Old 08-12-09, 05:36 PM
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Do you have a voltmeter ?
This is a job where the very first tool in your box that should come out is a voltmeter. There might be problems that are causing 24VAC to not get to the contactor in the AC condensor.
With out the volt meter you are just quessing.
 
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Old 08-12-09, 06:24 PM
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if you only shut the disconnect outside at the condenser you might of had 24Vs stil coming off the furnace from the stat cooling call and sparked a wire?do you have power at the stat...remove the stat and jump R to G for fan on the furnace if nothing thr TR is tripped or the fused link on the 24Vs is open need to change it....40VA 115/24V Grainger supply
 
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Old 08-18-09, 05:19 PM
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Thanks for the responses. Sorry i took so long to respond!! I just ordered a new transformer and hopefully i don't blow this one up. Now i have the new contactor wired. I have it wired so L1-white , L2- red, T1 Black, T2- red, the 2 yellow 24v to the top two terminals, smaller red and black wire to the back terminals of T2, and a purple wire to the back terminal of T1. These wire i cliped onto the back termals of T1 and T2 are the wires that i think could be wired wrong. I know the smaller red goes to T2 but just not sure of the black and purple wires. Any ideas?????
 
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Old 08-23-09, 03:54 PM
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There should be a wiring diagram on the lower door of the furnace and also one in the a/c electrical box. If not, provide the model and serial number for each and I will post the wiring diagrams for you to use.
 
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Old 08-23-09, 07:54 PM
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You may want to use an in-line 3amp fuse in the low voltage circuit so the fuse blows instead of the transformer.
Could help more if we had some pics of the electric compartment.
 
 

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