inside unit won't turn off..outside doesn't kick on


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Old 08-05-09, 10:22 AM
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inside unit won't turn off..outside doesn't kick on

My outside unit won't start..inside unit won't turn off unless I turn off at the breaker. I used a meter on the red to white as well as the red to blue (marked Y term.) and neither one showed any volts. (with the unit running of course). From what I've read here I think it might be the circut board...my unit might be stuck in heat mode...I'm not really sure. Any advice would be greatly appreciated!
thanks
 
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Old 08-05-09, 10:29 AM
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more info.

I should have noted...model is a comfortmaker model#epm24b15a1
 
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Old 08-05-09, 10:49 AM
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What position is the fan switch on the stat in?
 
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Old 08-05-09, 11:07 AM
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the fan switch is on auto. when I flip it to on I don't hear the fan speed up or slow down...and like I mentioned nothing turns it off.
 
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Old 08-05-09, 11:27 AM
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Check the low voltage fuse on the board. If no fuse check the transformer out put should be 24 volts.
 
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Old 08-05-09, 11:37 AM
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Could be a stuck relay or a low voltage short between R and G need to brake out the meter and start testing
 
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Old 08-05-09, 11:41 AM
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First, I really appreciate the help....inside the ac unit there are only 3 things...the circuit board, a round cylinder possibly a type of capacitor ( has 2 brown wires leading back to the fan/motor), and the third thing could be the transformer? It's square with 4 wires..one side a black and white, the other has a blue and yellow. They all lead to the circuit board. Also, I checked and there is no fuse on the board. If the square 4 wire thing is the transformer....would I test the black and white with my meter?
 
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Old 08-05-09, 11:52 AM
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Question for the AC pro's; will an issue with the high level float switch on the condensate pan/drain cause this? Reason I ask is that my sister recently had AC replaced and initially had a problem much like this and when the tech checked out, had wired the float backwards or some such.
 
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Old 08-05-09, 12:19 PM
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update. I located the transformer and have 24..actually 26 volts when I tested the blue and yellow wires. I tested all the wires on the circuit board that go to the thermostat. (common to red, white) and got nothing. I then disconnected all the wires...turned the breaker on and it still kicked on. I found a helpful guy at tech support who said if it kept running I probably have a bad board. Can anyone confirm this?
 
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Old 08-05-09, 12:36 PM
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"Tow Guy" - float swich typically breaks the Y circuit which would shut off the cond but shouldn't effect the blower.

BBanker - no way to confirm it from here, the G circuit should be your blower. So you disconnected all low voltage wires from the board and the blower still ran
 
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Old 08-05-09, 12:45 PM
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Originally Posted by dun11
"Tow Guy" - float swich typically breaks the Y circuit which would shut off the cond but shouldn't effect the blower.

BBanker - no way to confirm it from here, the G circuit should be your blower. So you disconnected all low voltage wires from the board and the blower still ran
I did test the G wire...nothing on the board gave me any volts and if that was a question...Yes, I disconnected all the low voltage (c, r, y,w and g)wires and it still turned on.
 
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Old 08-05-09, 12:51 PM
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Did you locate a low voltage fuse on the circuit board? Usually a 3 amp, purple blade type fuse, like used for cars.
 
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Old 08-05-09, 01:03 PM
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Originally Posted by Skip4661
Did you locate a low voltage fuse on the circuit board? Usually a 3 amp, purple blade type fuse, like used for cars.
No, I looked closely...no fuse on the circuit board.
 
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Old 08-05-09, 04:20 PM
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Look closer. Trace the wires from the transformer, they should go to a fuse and also to a thermal limit. Your Carrier model is different from many other brands in that there has to be 24 volts to the board in order for the indoor fan to be OFF. If you're not getting 24 volts to the board, the indoor fan will run full time.
 
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Old 08-05-09, 04:27 PM
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daddyjohn...what you're saying makes a lot of sense. I know I have 24 volts leaving the transformer and since I don't have a fuse (the blue and yellow from trans. to circuit board just plug in) then it seems my most likely problem is to replace the board? I haven't mentioned last few posts, but I really appreciate all the help I'm getting trying to figure this out!
 
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Old 08-05-09, 05:08 PM
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Last thing is the board.
You have 24 from the trans. You disconnected all control wires to the stat. Only thing left is the board.
 
 

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