The answer to 'my furnace repair won't turn on' is that there could be several common causes, including a tripped circuit breaker, a problem with the thermostat, or a malfunctioning ignition or control board. Symptoms may include the furnace not starting at all, the blower fan not turning on, or the furnace shutting off unexpectedly.
For simple issues like a tripped breaker or thermostat problem, a homeowner may be able to troubleshoot and resolve the issue themselves. However, for more complex problems with the ignition system or control board, it's generally best to call in a professional HVAC technician to diagnose and repair the issue properly.