Customer had no heat in home had turned all the power switches off, turned power switch on and system didn’t fire with the thermostat calling for heat, jumped thermostat wire at primary control and furnace came on, went to thermostat disconnected wires off thermostat and jumped at thermostat system didn’t come on, found broken thermostat wire from contraction that was done in the basement, added 20 feet of new thermostat wire and tested system, furnace came on tested system, fan came on everything operational, customer had changed filter, system does need a cleaning is pretty dirty inside burner chamber will need to schedule cleaning.