The answer to 'why is my air handler not turning on' is that there could be several common causes, such as a tripped circuit breaker, a problem with the thermostat, or issues with the air handler itself. The air handler is the indoor component of your HVAC system that circulates the conditioned air throughout your home.
Some common symptoms of an air handler not turning on include no airflow, the fan not running, and the system not responding to the thermostat. Potential solutions include checking the circuit breaker, inspecting the air filter, and ensuring the thermostat is set correctly. However, if you're not comfortable troubleshooting the issue yourself, it's best to call in a professional HVAC technician to diagnose and repair the problem.