The answer to 'why is my AC not turning on' is that there are several common causes, including a tripped circuit breaker, a faulty thermostat, or issues with the condenser unit. The symptoms may include the unit not powering on at all, the fan not running, or the compressor not kicking in.
First, check the circuit breaker to see if it has been tripped. If so, reset the breaker and try turning the AC back on. If the breaker trips again, there may be an electrical issue that requires a professional HVAC technician to diagnose and repair.
Next, examine the thermostat to ensure it is set to 'cool' and the temperature is set lower than the current room temperature. If the thermostat appears to be functioning properly, the issue may be with the condenser unit outside. Inspect the condenser for any visible damage or obstructions, and make sure the fan is running. If the condenser is not working, it's best to call in a professional HVAC technician to further investigate the problem.