It really stinks to have your furnace not come on when you really need it. Though the problem is likely beyond your ability to fix, there are a few things you can do before calling an HVAC technician to look at it for you. After all, investigating the issue is better than sitting in your cold house, waiting for the problem to resolve itself. Let’s take a look at what you should do when your furnace refuses to come on.
Check the Thermostat
The thermostat is one of the core components of your furnace. It is responsible for controlling pretty much everything your furnace does, including turning on and off. This means that if your thermostat malfunctions for any reason, it can pretty easily stymie an otherwise healthy furnace from operating. Have a look at your thermostat’s display and make sure that the temperature and settings are correct. Solving your problem may be as simple as pressing a few buttons. If everything seems to be correct, then the problem might lie elsewhere. Your professional HVAC technician will check the thermostat more thoroughly, to make sure it’s operating properly.
Check the Pilot Light
Not all furnaces use standing pilot lights anymore, those tiny flames that continuously burn underneath the burner assembly. If your furnace happens to still use one, though, look and see if it’s still burning. If the pilot light is out, that is probably the source of your problem. You can try re-lighting it yourself, if you know how to do so. If you don’t, don’t worry. All HVAC technicians know how to re-light pilot lights. If your pilot light refuses to stay lit after you try lighting it, then you probably have a faulty thermocouple.
The thermocouple is a device that is designed to regulate the amount of gas the pilot light receives. If the pilot light is lit, the thermocouple makes sure that it receives a steady flow of gas to keep it alive. If the pilot light goes out, the thermocouple closes the gas valve as a safety measure. A faulty thermocouple will often smother a pilot light by cutting off the gas flow prematurely, smothering the flame. If your thermocouple is broken, you’ll need a professional to replace it.