If you have your thermostat set to a overheated temperature but you have noticed that it’s not turning on, you’re likely experiencing a minor issue that you may luckily be able to service yourself. If your furnace is not turning on, you should beginning by checking your thermostat, air filter, circuit breaker, blower cover, condensate pump plus line, plus furnace switches. If your furnace is not turning on, the first thing you should do is check your thermostat plus make sure the batteries are not dead, plus the setting is on heat plus fan setting is on auto. If your thermostat is not on heat plus 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 furnace, which can cause your furnace to overheat plus shut off; Filters should be updated every 1-3 weeks. The circuit breaker tripping can also be a cause of the furnace not running constantly. If the circuit labeled furnace has moved to the middle or neutral position, the breaker has tripped. Turn it off plus back on. If your furnace was recently took care of or you took the cover off of your furnace to check something, the blower cover may not be on as tightly as it needs to be. Many gas furnaces have a safety feature called a blower door safety switch that prevents the furnace from turning on if the blower cover is not secured tightly. If there is a block in the condensate pump or drain line, water may back up in the system, triggering the system to shut down to prevent water destruction. If there is a blockage, a corporation will have to clear it. There are a variety of safety switches in your furnace that each monitor a particular area of your furnace plus will trigger the system to shut down if that area is not toiling constantly. Be sure to check the pressure switch, flame sensor, limit switch, plus flame rollout switch! You might need to learn your furnace manual to get a better system of which switch is indicating a problem. You can also make the decision to call a Heating & Air Conditioning professional to diagnose the problem.