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Commander Air Inc. Blog

Furnace Not Working All of a Sudden? It Might Be This Little Sensor

graphic-of-an-orange-flame

When a furnace completely stops working during the coldest depths of winter, it’s a huge problem. You can’t wait around for repairs until you get hypothermia and fall over like a frozen iguana dropping out of a tree! But we’ve got some excellent news for you. One of the most common causes of a sudden furnace breakdown is actually very simple.

There are safety mechanisms built into your furnace. This protects you from things like gas leaks and carbon monoxide poisoning. One part of your furnace’s safety system is called the flame sensor. It’s very easy for it to stop working properly, and lucky for you, it’s also easy to fix.

How Your Furnace Fires Up

A gas furnace has a large number of components, but we’ll focus on the basics for now. In order to get the burners lit, there is either a pilot (in an older furnace) or an ignition system (which is what all newer furnaces have). In either case, there must be a flame in order for the furnace to release the gas that will fire up the burners.

The flame sensor is the component that determines whether the flame is indeed present. If no flame is detected, it would be very dangerous for your furnace to release gas that won’t be properly combusted. So your furnace requires the go-ahead from the flame sensor to release that gas. But what if the flame sensor doesn’t detect a flame?

When the Flame Sensor Shuts the Furnace Down

There are two reasons why the flame sensor might cause the furnace to shut down. The first is probably obvious: there is no flame. Either your pilot light has gone out, or your ignition system is failing to get a flame started. While your owner’s manual will have instructions for safely relighting a pilot, an ignition system problem is something that will require professional attention.

But the second reason for the flame sensor to shut the furnace down would be that it is simply failing to detect a flame even though the flame is, in fact, present! Why would it be unable to sense the flame? Put plainly, it’s just too dirty. Carbon from being part of a combustion system or just ordinary caked-on dust can make it so the flame sensor cannot sense.

How to Resolve the Problem

If your furnace does have a pilot light, check whether it’s out, and if so, follow the instructions to relight it. If the pilot won’t stay lit, or if you have an ignition system, you’ll need furnace services in Bellview, FL. Your technician can determine the exact cause, and either (or both) the ignition system or the flame sensor can be disassembled and carefully cleaned.

Avoiding the Problem in the Future

The best way to prevent this from happening is by getting annual maintenance done on your furnace, ideally during the fall, but more importantly, every single year regardless of the exact season. Maintenance involves disassembling and cleaning all the components and will eliminate problems like dust and carbon buildup before they cause your furnace to stop working.

Whether you have a simple question about re-lighting your pilot, need furnace maintenance, or require repair, we’ll always be happy to help.

Contact the team at Commander Air Inc. Your hometown heating and cooling specialist for three generations.

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