If you ever take a close look at your home’s furnace, you should notice a small red LED light located somewhere on a side panel. No, this light isn’t just an ‘On’ indicator; instead, it is a way to communicate with you about its current status. Manufacturers came up with this creative way of communication years ago, and its use is now widespread enough where you can be confident your unit utilizes this concept. Let’s learn more about how it works.

Are you familiar with Morse Code? Well, our home’s furnaces use a similar system, although one much easier to understand. Instead of dots and dashes representing letters, they express numbers in this system, much more straightforward. When broken down into its simplest sense, the number of blinks between a pause is the error code. And while the shortest codes may be single-digit codes, some more complex ones maybe double digits. In a system like this, dashes will represent the second number. Confused? Probably. Here are a few examples to help you out.

dot, dot, pause, dash, dash, dash = 23

In the example provided above, when your light quickly flashes twice, it represents the number two. Then, after a brief pause, it is followed by three dashes, meaning 3 or 23 when combined. Here are a few more examples:

dot, dot, dot, dot, dot = 5

dot, pause, dash, dash = 12

The next step is to reference the code chart. In most instances, usually located directly on the furnace itself. If not, it will be in your manual, or you can find it by a quick Google search. Matching the code with the corresponding error on your chart will help you identify the problem with your furnace and the suggested repair needs. If you are lucky, this may be a simple DIY fix. However, this may not always be the case. We recommend expert help for fixes that require a certified HVAC skillset or knowledge.

Now that we know what the light means when it’s blinking, what does it mean when doing something else? If your light is a steady red, that is a good sign; all systems function properly. If you notice the light is out, this is a sign that your furnace is not receiving power and will likely not be working. More often than not, this means your system has blown a fuse, which is resolved by a short trip to your fuse box

Regardless of your unit’s current functionality, it is a good idea to check your red light occasionally. Although everything may seem fine, there could be an underlying issue that needs prompt addressing and repair. Trust us when we say it could save you a big headache down the road.