Furnace troubleshooting

Most Common Lennox® Furnace Error Codes (and What They Mean)

While your Lennox® heater isn’t able to speak to you, it possesses a method to tell you about a furnace error.

Its control board has double LED lights that can display a fault code. Depending on the malfunction, your furnace might use solid or flashing lights.

Although there are a few simple heating adjustments you can complete on your own, most tasks are best left to the professionals. When your heater refuses to start or provide heat, call McFadden Heating & Cooling at 1-866-781-0111 for experienced furnace repair in Dresden.

Our technicians will speedily identify and handle the problem, even if you don’t use a Lennox heating system. We can repair all brands or configuration—and get the comfort reintroduced to your house without delay.


What Does the Blinking Light on My Furnace Mean?

Your heating system depends on lights to flash code when it isn’t working right. It also engages these lights to let you know it’s operating properly.

Correct heating consists of:

  • Concurrent slow flash—heating system operating like it should.
  • Both lights flash fast—heating system is initiating the call for heat.

If you notice a lone light blinking slowly and the other going on and off rapidly, your furnace could have a low flame signal. This can happen even when your heating system is heating properly. It means the flame sensing rod could need to be cleaned or in the wrong spot on the burner. Reach out to us at 1-866-781-0111 for help.

Here are a few other of the most routine faults for Lennox heaters.

Heating System Refuses to Turn On

Here are many of the light arrangements you may see when your heat will not or keep operating. The majority of these problems need to be fixed by a technician, like one from McFadden Heating & Cooling.

  1. The pair of LED lights are extinguished. This means your furnace might not have power. Go to the breaker box to confirm the furnace fuse isn’t triggered. Attempt to reset the fuse if it has moved into the “off” spot. If it instantly trips after you reset it, leave the breaker alone and call us at 1-866-781-0111.
  2. A single light is solid and the other is flickering slowly. This shows the flame rollout switch is may be malfunctioning. The part is an important safety device that helps in avoiding fires and carbon monoxide. You shouldn’t attempt to handle this issue without professional help.
  3. A single light is blinking quickly and the other is flashing slowly. This likely indicates power polarity has been inverted. Your heating system might have a wiring issue that calls for professional aid from McFadden Heating & Cooling.
  4. The duo of lights are flickering slowly. This means your heater’s blower motor probably isn’t working. This component distributes hot air from the heater into your house. We can help in pinpointing what’s causing a problem with this part.
  5. A single light is blinking slowly and the other is flashing rapidly. This indicates your furnace may have not enough voltage or a short circuit. Reach out to our experts at 1-866-781-0111 for help.
  6. One light is flashing on, on and off while the other blinks on, off, on. This means there might be an error with your heater’s control panel or wiring. McFadden Heating & Cooling can pinpoint the issue and take care of it.
  7. Both lights are using alternating slow blinks. This indicates your heating system likely has a flame problem. There might be a problem with its gas supply, gas valve or ignitor control. Call us at 1-866-781-0111 for assistance.
  8. A single light blinks slowly while the other stays solid. This often signifies your furnace’s limit switch is not working. The switch prevents your HVAC equipment from becoming too warm. Reach out to the pros at McFadden Heating & Cooling for assistance.

Heating System Blower Runs But No Warmth

Here’s what might be wrong when you hear your furnace’s blower fan running, but you aren’t gaining any warm air.

  • The pair of lights display every other rapid flickers. This indicates your furnace ignitor may be broken. This piece kindles gas in your HVAC equipment to make warmth and should be repaired by a professional from McFadden Heating & Cooling.

Depend on Us for Professional Furnace Repair

When you have to get your heating system repaired fast, trust the technicians at McFadden Heating & Cooling. Our technicians will fix the problem without delay and have your residence feeling cozy again soon. Contact us at 1-866-781-0111 or contact us online to get an appointment now.

Back To Blog