AC does not turn on..Bad thermostat?


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Old 06-05-10, 11:46 AM
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AC does not turn on..Bad thermostat?

Hi all,

Trying to turn on my Air Conditioning upstairs first time this year. But it won't turn on no matter how cold I set my thermostat. I've also tried to set to heat or fan on. But no luck. The fuse in the thermostat seems to be fine. I also checked the breaker outside. I don't see any issues. Oh.

I don't think my AC, furnace or fans are all bad at the same time. Is the thermostat back? I want to hear expert's advices before run out to get one. Or anything I should try?

Thank you very much!
 
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Old 06-05-10, 11:52 AM
Tolyn Ironhand's Avatar
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Jumper between terminals to see if anything will run. On a forced air furnace with outside condenser the terminals are (normally) :

R = power to the stat
w = heat
g = fan
y = cool

So if you jump between R and G the fan should turn on.
 
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Old 06-05-10, 12:37 PM
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Thanks for your reply. I jumped between R & G in the thermostat upstairs and the fan still didn't run. I've tried the same method downstairs and worked, so I did it correctly. Looks like it's not thermostat then. Any suggestion on what I should try now? Thanks.
 
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Old 06-05-10, 12:46 PM
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Are the thermostats running separate units or are they paralleled?

If they are separate I would start at the furnace and jump the R and G terminal there and see if the fan runs. If it does not, then make sure the furnace has power. (Note: There is many times a safety button that must be held down for the furnace to run) If it does run then you might have a bad/broken cable going to the stat.
 
 

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