The answer to 'my central air won't turn on' is that there could be several common causes, such as a tripped circuit breaker, a faulty thermostat, or issues with the compressor or other components. Symptoms may include the air conditioner not powering on at all or the fan running but no cool air being produced.
For simple issues like a tripped breaker or clogged air filter, you may be able to troubleshoot and fix the problem yourself. However, for more complex problems with the compressor, refrigerant lines, or electrical system, it's best to call in a professional HVAC technician to diagnose and repair the issue.