The answer to 'my furnace 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 furnace itself. First, check the circuit breaker to see if it has tripped and needs to be reset. If that doesn't solve the issue, the next step is to check the thermostat to ensure it's properly programmed and functioning correctly. If those two basic troubleshooting steps don't resolve the problem, it's likely that there is a more complex issue with the furnace that will require the expertise of a professional HVAC technician.
While some basic furnace troubleshooting can be done by homeowners, it's generally best to call in a professional HVAC technician if the furnace won't turn on or if you're unsure of the cause. Attempting to repair a furnace without the proper knowledge and tools can be dangerous and may even cause further damage to the system.