Air Conditioning - Fan won't come back on in AUTO mode
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AlanM
04-29-09, 10:33 AM
When I run my AC it starts up fine. The unit outside cranks up then the fan inside begins to circulate the air. When it reaches the designated temperature it shuts off like it should. But here's the problem, when the thermostat cranks it back on the outside unit starts up but the indoor circulation fan won't. My only workaround is to set the fan to ON mode rather than automatic. But I hate running the fan all the time and wasting the electricity. Any suggestions on how to fix this?
jim-connor
04-29-09, 10:38 AM
What brand of equipment? Is this variable speed? Some model numbers would help too.
AlanM
04-29-09, 10:57 AM
The brand is Janitrol. The outside unit model number is CPKJ36-1AB. The inside unit model number is A42-10. I don't know if it's variable speed.
I recently replaced the thermostat hoping it would fix the problem. I have a picture of the old wiring if that will help:
Edited out links to photos
I recently replaced the thermostat hoping it would fix the problem. I have a picture of the old wiring if that will help:
Edited out links to photos
jim-connor
04-29-09, 11:32 AM
I suspect it's your blower time delay relay. When these go bad, blower start-up may or may not occur. This is a common failure item. The part number (from memory here, so don't hold me to it) is B13707-38.
As a primative test, you could carefully tap the relay while the thermostat is calling for cooling and the blower failed to start. USE CAUTION HIGH VOLTAGE.
If you have a meter it would help. You should have 240 volts at the blower motor when 24 volts is applied to the relay coil. This unit has an on delay of about 5 to 15 seconds and a off delay of about 30 to 60 seconds.
However, if you don't have the 24 volts to the coil, I would examine the thermostat and low voltage wiring.
As a primative test, you could carefully tap the relay while the thermostat is calling for cooling and the blower failed to start. USE CAUTION HIGH VOLTAGE.
If you have a meter it would help. You should have 240 volts at the blower motor when 24 volts is applied to the relay coil. This unit has an on delay of about 5 to 15 seconds and a off delay of about 30 to 60 seconds.
However, if you don't have the 24 volts to the coil, I would examine the thermostat and low voltage wiring.
AlanM
04-29-09, 11:47 AM
Thank you very much, Jim. Now that you sent me in the right direction I'll hopefully get this thing fixed. Again, thank you.