Question My a/c will run fine for as long as 2-6months, then suddenly start acting as if it has a mind of it's own...While blowing cold air, it will suddenly start blowing hot air...If you go out to the main unit, you can see that the fan is not running the compressor not running (contacts are free-not pulled down)If I press down on the contact bridge w/a screw driver, it will engage the compressor...
The only way to "clear" this is to turn off the thermostat and the Blower inside...wait a few minutes, and power it back up...it will then work for a few hours to a few months, before doing it again...
My first thought was the thermostat, but it is getting power and working the "contacts"...It acts like the A/C thinks it is freezing and kicking into freeze mode...any thoughts?
Answer It would be difficult to tell without knowing more about the system. It seems as though you are not getting 24 volts to the contactor coil intermittently. You would have to trace the 24 volt circuit back from the contactor when it is not working to see where you are losing voltage in the circuit.
