The answer to 'my HVAC repair won't turn on' is that there could be several common causes, such as a tripped circuit breaker, a faulty thermostat, or a problem with the HVAC unit itself. Symptoms may include the unit not powering on at all, or the fan not running when the thermostat is set to cool or heat.
If the issue is a tripped circuit breaker, you can try resetting it. However, if the breaker keeps tripping, there may be an underlying electrical problem that requires a professional HVAC technician to diagnose and repair. Similarly, if the issue is with the thermostat, you may be able to replace the batteries or reset the thermostat, but a malfunctioning thermostat often requires professional replacement.