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

December 06, 2019

While your Lennox® heating system can’t talk to you, it possesses a process to communicate a furnace error.

Its control board has twin LED lights that can share a fault code. Depending on the problem, your heating system may display steady or flashing lights.

Although there are certain simple heating fixes you can do yourself, the majority of fixes are best left to the professionals. When your furnace will not kick on or give warmth, call Thurston Heating & Air Conditioning at 308-624-3485 for professional furnace repair in Kearney.

Our specialists will quickly identify and repair the malfunction, even if you don’t use a Lennox heater. We can fix all types or makes—and get the heat returned to your residence quickly.


What Does the Flashing Light on My Heater Mean?

Your heating system uses lights to flash code when it is malfunctioning. It also engages this setup to relay it’s running correctly.

Correct heating includes:

  • Both lights flash slowly—heating system working correctly.
  • Concurrent fast flash—furnace is initiating the call for heat.

If you notice one light flashing slowly and the other flashing quickly, your furnace might have a low flame signal. This can occur even when your heater is working correctly. It means the flame sensing rod may have build-up or in the wrong area on the burner. Contact us at 308-624-3485 for help.

Here are several other of the most routine errors for Lennox furnaces.

Heating System Will Not Start

Here are some of the light sequences you could see when your heater refuses to or keep running. The majority of these issues have to be repaired by a professional, for instance from Thurston Heating & Air Conditioning.

  1. All LED lights aren’t lit. This means your heater might not have power. Find the breaker box to confirm the heating system fuse hasn’t triggered. Attempt to reset the fuse if it’s in the “off” position. If it immediately turns off after a subsequent reset, leave the breaker alone and call us at 308-624-3485.
  2. A single light is solid and the other is blinking slowly. This shows the flame rollout switch is possibly open. The switch is an important safety tool that assists in preventing fires and carbon monoxide. You shouldn’t attempt to fix this fault without professional help.
  3. One light is blinking quickly and the other is flashing slowly. This usually indicates power polarity has been transposed. Your heating system might have a wiring fault that requires expert aid from Thurston Heating & Air Conditioning.
  4. The pair of lights are flashing slowly. This indicates your heater’s blower motor likely isn’t working. This component circulates warm air from the heater into your rooms. We can aid in figuring out what’s wrong with this part.
  5. An individual light is blinking slowly and the other is flashing quickly. This signifies your heating system might have not enough voltage or a short circuit. Contact our specialists at 308-624-3485 for help.
  6. One light is blinking on, on and off while the other blinks on, off, on. This signifies there may be a problem with your HVAC system’s control panel or wiring. Thurston Heating & Air Conditioning can pinpoint the error and handle it.
  7. The pair of lights display every other slow blinks. This means your furnace likely has a flame issue. There may be an issue with its gas supply, gas valve or ignitor control. Get in touch with us at 308-624-3485 for assistance.
  8. One light flashes slowly while the other remains solid. This often indicates your heater’s limit switch is malfunctioning. The switch stops your HVAC system from overheating. Get in touch with the pros at Thurston Heating & Air Conditioning for assistance.

Furnace Blower Runs But No Warmth

Here’s what could be wrong when you observe your heating system’s blower fan on, but you aren’t receiving any heated air.

  • The pair of lights are showing every other rapid flickers. This signifies your furnace ignitor could be broken. This piece lights energy in your HVAC equipment to make warmth and should be fixed by a professional from Thurston Heating & Air Conditioning.

Depend on Us for Professional Furnace Repair

When you have to have your heater fixed fast, depend on the specialists at Thurston Heating & Air Conditioning. Our pros will repair the error right away and have your rooms feeling relaxing again in a short time. Call us at 308-624-3485 or contact us online to request an appointment today.