If you have your temperature control set to a warm temperature however you have noticed that it’s not turning on, you’re likely experiencing a minor issue that you may luckily be able to repair yourself. If your gas furnace isn’tturning on, you should beginning by checking your temperature control, air filter, circuit breaker, blower cover, condensate pump and line, and gas furnace switches. If your gas furnace isn’tturning on, the first thing you should do is check your temperature control and make sure the batteries are not dead, and the setting is on heat and fan setting is on auto. If your temperature control is not on heat and auto and/or doesn’t have fresh batteries, it may not turn on. If everything is well, then you should next check your air filter. If your filter is clogged, it will reduce the airflow to your gas furnace, which can cause your gas furnace to overheat and shut off, and filters should be replaced every 1-3 weeks. The circuit breaker tripping can also be a cause of the gas furnace not running properly. If the circuit labeled gas furnace has moved to the middle or neutral position, the breaker has tripped. Turn it off and back on. If your gas furnace was recently tested or you took the cover off of your gas furnace to check something, the blower cover may not be on as tightly as it needs to be. Many heating systems have a safety feature called a blower door safety switch that prevents the gas furnace from turning on if the blower cover isn’tsecured tightly. If there is a block in the condensate pump or drain line, water may back up in the system, triggering the idea to shut down to prevent water disfigure. If there is a blockage, a supplier will have to clear it. There are a variety of safety switches in your gas furnace that each monitor a particular section of your gas furnace and will trigger the idea to shut down if that section isn’tworking properly. Be sure to check the pressure switch, flame sensor, limit switch, and flame rollout switch, but you might need to learn your gas furnace manual to get a better idea of which switch is indicating a problem. You can also make the decision to call a Heating, Ventilation as well as A/C professional to diagnose the problem.