Skip to content
(716) 648-4257

Available Day or Night

What’s that Light on my Furnace?

What’s that Light on my Furnace?

Most modern day furnaces have a red light to allow your furnace to communicate with you.

Whether you recently had a new furnace installed or just so happened to notice a red light on your furnace, you may be asking, “What’s that light on my furnace”? While all furnaces are different, most modern day furnaces have a red light to allow your furnace to communicate with you.

We review what your furnace may be trying to say, below.

I don’t have a light on my furnace. Should I be concerned?

Not all furnaces are built with an indicator light, especially if you have an older unit. If you don’t have a light on your HVAC unit, there is no reason to be concerned. If there are ever problems with your heater, local Western New York heating professionals can help you solve and resolve them without the light.

The light on my furnace is solid. What does that mean?

If your furnace light is a solid color, that is typically an indication that all is well with your unit. In most cases, this light remains solid while your furnace is on, with power to it, letting you know that your furnace is working as it should be.

I thought I saw a light, but now it is gone. Is there something wrong?

If there is a light on your furnace and it goes out completely or isn’t on at all, that generally means that there is no power to the unit. Check to make sure the power source is connected. If you can’t determine what is preventing your unit from getting power, call in a heating expert to help, so you can avoid a cold day and night for you and your family.

What’s that light on my furnace and why is it blinking?

Your furnace can’t talk, so when there are issues with it, it uses this light to communicate and provide a code as to what is wrong. If you notice that your furnace light is blinking, this usually means that your furnace is not functioning properly and there is a problem with.

Think of the blinking light as Morse code. If you can catch the blinking code, write it down. The code can help you determine what the problem is. Furnaces usually have a code chart on them that can help you decipher the code.

Below are some common reasons for the furnace light blinking. Keep in mind, as we said before, all furnaces are different, so if in doubt, call in a professional.

Ignition Failure or Fault: An error with the gas, ignition failure, or flame can cause the red light to start blinking. This could be an indication that your flame sensor is dirty, and/or could also mean there is a problem with the gas valve or igniters.
Pressure Switch Inducer Issue: A furnace pressure switch is a safety device located near the draft inducer motor of a gas forced-air furnace. Inducers and pressure switches are parts of the furnace that make sure the furnace is venting unwanted gas. The blinking light could indicate that there is a blockage or other issue preventing these components to function as they should.
Roll-out Switch Problem: A roll-out switch is a safety feature on gas furnaces. This switch stops the furnace from igniting if the part of the furnace that is supposed to stay cool gets too hot. Heat being detected where it shouldn’t be in your furnace, is a problem. This is usually caused by an issue with your air filter being blocked and dirty, but you should call a heating expert to help you confirm the problem is not larger.
Furnace ‘Lock Out’: Modern furnaces have several safety sensors that keep track of furnace operation. The furnace controller monitors these sensors constantly. If one of the sensors reports an unsafe condition, the furnace controller shuts off fuel and power to prevent unsafe operation. This condition is known as ‘lock out’. A furnace ‘lock out’ occurs when a furnace has attempted to fire multiple times but has failed to ignite. A ‘lock out’ can usually be resolved by powering off your furnace for a few minutes and then turning it back on.

Now that you know what that light on your furnace is, you should keep an eye on this indicator to ensure it is not trying to tell you something.

At Duffett Plumbing, Heating & AC, we are trusted experts when it comes to Western New York heating issues. We offer emergency heating repair in Hamburg, NY and beyond. Call us, and we’ll send one of our professional technicians to your home to inspect, diagnose, and repair your system.