My thermostat's LCD is showing "OL". When I switch to Air Conditioning it will not do anything like it's dead. I turn off my breaker for the airconditioning/heater unit and try to power it again it will not do so. Can you tell me what "OL" means? Can I fixed it myself?

It would be nice to know what brand and model number.

I feel like guessing or mind-reading today: Lux Products Corporation

Sounds like a hunter to me