Proper Heating and Air Conditioning service can help you avoid various correct condensing gas furnace complications, but even so, your condensing gas furnace may, at some point in its lifespan, cut down, and troubleshooting it may help restore its operations. Begin your condensing gas furnace troubleshooting at the thermostat, make sure that your thermostat is on heat mode and its setting is above your room temperature, however it is best to set it to the highest possible setting while you carry out the troubleshooting procedure. If the condensing gas furnace fan is not working, set the fan at the on mode, check the fuse, breaker, and switch for the condensing gas furnace. If the circuit breaker tripped, leave it off and proceed to check the wiring for any loose attachions, then look for burn signs on your control board and substitute the board if you find any burn spots. If there are no blown fuses or the breaker wasn’t tripped, check the inspection window of your blower compartment on your gas furnace… There should be a flashing red light. If there is no light, neither red nor red, the issue could be your transformer, gas furnace control board, thermostat, blower motor, or the run capacitor. If your condensing gas furnace uses a standing pilot, make sure that it is on, and the flame is reaching the tip of your thermocouple. If the pilot light is on, but the main gas furnace burners do not come on, suppose the side of your condensing gas furnace. If the side is cool, the issue could be the gas furnace control board, thermostat, valve, or limit control. If the side is warm, allow your gas furnace to cool before continuing to troubleshoot.