AC will not shut off on colman presidential II

[toiletduck]

Hi, when starting my ac for the first time this year i have been having some problems. Sometimes the ac just will not stop and i will find it down to 55 degrees before i can flip the breaker. I have tried changing the thermostat, it is a 2 wire so also tried directly connecting and disconnecting the 2 wires and it does nothing. The only way to shut off the inside blower and outside condenser/fan is to flip the breaker. It does this every other day, not all of the time.

I have no problems with the heat, it works just fine. Just the ac gives me problems. Last year it happened a few times and just ignored it, but this year its doing it more often.

The number on the ac blower is- 7900-6821

The number on the control box is- 7900-305

The number on the lower furnace is- 7966-856

The number on the outside condenser is- 7830-901


I can replace the parts myself, I just dont know what is broken.

Thanks for the help!!!!

[Robert]

Hi,

At the t-stat, did you remove both wires and leave disconnected and it still did it and it wouldn't shut off with both wires disconnected ?


If so, that rules out the t-stat.


Next would be the t-stat reversing relay inside the a/c control box at furnace.


Thanks,
Robert

[toiletduck]

That is correct, plus i have tried several different t-stats and like I said the weird part is the furnace has never given me any problems shutting off, its just the ac.

[Robert]

Hi,

You should have two control boxes, one down lowest for heating and one above or mounted to front of blower housing for cooling.

The model number you gave does not show as valid.


Can you be sure it is correct and also that it is the a/c control box model number.

Need to see which thermostat reversing relay you have , as that is most likely your problem.


Go here and look on right side for T-Stat Reversing Relay # 7670 - 3071 :

http://www.mobilehomerepair.com/ColemanAC.html


That is the reversing relay shown for the a/c control box listed for your furnace. However, there are other control boxes and reversing relays that would work, so need to know which yours has.


Thanks,
Robert