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

Feb 22, 2024


Jake Nielson


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

Its control board has two LED lights that can display a fault code. Subject to the issue, your heater could use continuous or flashing lights.

While there are various elementary furnace repairs you can take care of on your own, the majority of tasks are best left to the professionals. When your heater will not kick on or give heat, contact Schraer Heating & Air Conditioning at 636-456-5041 for professional furnace repair in Warrenton.

Our specialists will swiftly detect and fix the breakdown, even if you don’t use a Lennox heater. We can service all kinds or configuration—and get the comfort reintroduced to your residence fast.

What Does the Flashing Light on My Furnace Mean?

Your furnace depends on lights to flash code when it is malfunctioning. It also works this setup to let you know it’s heating correctly.

Regular operation involves:

  • Simultaneous slow flash—heating system operating like it should.

  • Simultaneous fast flash—furnace is starting to call for heat.

If you see a solitary light flashing slowly and the other blinking fast, your furnace could be experiencing a low flame signal. This can happen even when your heater is working correctly. It signifies the flame sensing rod may be dirty or in the bad location on the burner. Contact us at 636-456-5041 for support.

Here are some of the most typical problems for Lennox furnaces.

Furnace Won’t Kick On

Here are some of the light patterns you might notice when your heating system refuses to or keep heating. Most of these problems have to be fixed by an expert, for instance from Schraer Heating & Air Conditioning.

  1. The duo of LED lights are extinguished. This indicates your heating system might not have electricity. Examine the breaker box to confirm the heating system fuse is not flipped. Attempt to reset the fuse if it’s in the “off” spot. If it promptly trips after a subsequent reset, don’t touch the breaker and call us at 636-456-5041.

  2. An individual light is continuous and the other is blinking slowly. This implies the flame rollout switch is may be malfunctioning. The switch is a critical safety device that assists in avoiding fires and carbon monoxide. You shouldn’t attempt to fix this issue on your own.

  3. An individual light is blinking quickly and the other is blinking slowly. This likely signifies power polarity has been transposed. Your heating system may have a wiring fault that calls for expert help from Schraer Heating & Air Conditioning.

  4. The duo of lights are flashing slowly. This signifies your heating system’s blower motor likely isn’t working. This component sends hot air from the heater into your rooms. We can help in determining what’s causing a problem with this part.

  5. One light is blinking slowly and the other is flickering fast. This indicates your heater could have insufficient voltage or a short circuit. Call our technicians at 636-456-5041 for support.

  6. One light is flickering on, on, off while the other flashes on, off, on. This indicates there could be a malfunction with your heater’s control board or wiring. Schraer Heating & Air Conditioning can find the error and handle it.

  7. Both lights show every other slow flickers. This indicates your HVAC system may have a flame failure. There may be trouble with its gas supply, gas valve or ignitor control. Contact us at 636-456-5041 for support.

  8. A single light flickers slowly while the other is steady. This typically signifies your HVAC equipment’s limit switch is not working. The switch prevents your HVAC system from overheating. Reach out to the specialists at Schraer Heating & Air Conditioning for assistance.

Heater Blower Operates But No Warm Air

Here’s what might be wrong when you hear your heating system’s blower fan on, but you aren’t receiving any warmth.

  • Both lights are giving every other quick flashes. This indicates your furnace ignitor could not be in working order. This component lights energy in your heater to produce heat and should be serviced by a specialist from Schraer Heating & Air Conditioning.

Depend on Us for Expert Furnace Repair

When you have to get your heater in working order without delay, trust the specialists at Schraer Heating & Air Conditioning. Our technicians will repair the issue right away and have your rooms feeling comfortable again in no time. Reach out to us at 636-456-5041 or contact us online to get an appointment now.