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Why Won’t My Furnace Start?

It’s a pretty horrible feeling to try to turn on your furnace on a cold day and have it refuse to start. Furnaces tend to be pretty reliable as heating systems, but that doesn’t make them immune to problems. There are a few different factors that may be contributing to your furnace’s inability to start. Let’s take a look at some of the most common ones.

Malfunctioning Thermostat

The thermostat serves the same purpose in the heating system as your brain does in your body. It is responsible for controlling the furnace, deciding when it comes on and when it doesn’t. A problem with your thermostat, therefore, can stymie even a healthy furnace. Check your thermostat and make sure that everything is set properly. If the thermostat is set to “heat” or “fan” and the temperature seems to be reading correctly, then the problem is likely with your furnace. There is a chance that there is still a problem with your thermostat’s control board, but you’ll need a professional to confirm that.

Pilot Light is out

After the thermostat, the most common cause of a furnace not starting is the pilot light. The pilot light is a flame that burns under most furnaces 24/7, and is responsible for starting the furnace by igniting the burners. Pilot lights have a reputation for blowing out every now and then, rendering the furnace without an ignition source. The easiest way to check if your pilot light is out is by looking under your furnace, or in the small window included on some models to shield the chamber. If you can see the pilot light burning, then it probably isn’t the issue. If the pilot light is out, you’ll need to re-light it or have a professional do it for you.

A separate issue involves the pilot light refusing to stay lit, which is usually caused by a faulty thermocouple. The thermocouple is a sensor that controls the gas valve for the pilot light. A malfunctioning thermocouple can cut off the gas flow and smother the pilot light prematurely.

If you’re having issues with your furnace, call Comfort Flow Heating. We provide heating services throughout Eugene.

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