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

December 06, 2019

While your Lennox® heater cannot talk to you, it does have a procedure to tell you about a furnace error.

Its motherboard has two LED lights that can share a fault code. Depending on the issue, your heater could display continuous or flashing lights.

Although there are various simple furnace adjustments you can do yourself, the majority of repairs are best taken care of by the professionals. When your heating system won’t turn on or put out warmth, reach out to Lanz Furnace and Fireplace at 608-291-3606 for expert furnace repair in Monroe.

Our technicians will speedily pinpoint and take care of the failure, even if you don’t own a Lennox furnace. We can fix whichever brands or makes—and get the comfort restored to your home quickly.


What Does the Flickering Light on My Heater Mean?

Your heating system depends on lights to flash code when it requires repairs. It also engages this system to tell you it’s running like it should.

Normal heating involves:

  • Simultaneous slow flash—heater working properly.
  • Concurrent fast flash—furnace is initiating the call for heat.

If you see a lone light flashing slowly and the other blinking fast, your heating system may be having a low flame signal. This can take place even when your heating system is running correctly. It means the flame sensing rod could need to be cleaned or in the bad area on the burner. Call us at 608-291-3606 for help.

Here are some of the most typical issues for Lennox HVAC systems.

Furnace Will Not Turn On

Here are some of the light arrangements you may notice when your heat refuses to or stay on. The bulk of these errors must be repaired by a technician, such as one from Lanz Furnace and Fireplace.

  1. Both LED lights are extinguished. This indicates your heating system might not be receiving power. Find the breaker box to confirm the heater fuse is not triggered. Try resetting the fuse if it’s in the “off” spot. If it immediately turns off following a reset, don’t touch the breaker and get in touch with us us at 608-291-3606.
  2. A single light is solid and the other is blinking slowly. This shows the flame rollout switch is may be malfunctioning. The switch is an essential safety mechanism that aids in preventing fires and carbon monoxide. You shouldn’t try to handle this issue yourself.
  3. An individual light is flickering quickly and the other is flashing slowly. This typically indicates power polarity has been inverted. Your furnace could have a wiring issue that requires specialized assistance from Lanz Furnace and Fireplace.
  4. All lights are flickering slowly. This means your furnace’s blower motor probably isn’t running. This component moves warm air from the HVAC system into your house. We can assist in figuring out what’s wrong with this part.
  5. A single light is flickering slowly and the other is flickering quickly. This means your HVAC system may have insufficient voltage or a short circuit. Get in touch with our specialists at 608-291-3606 for support.
  6. One light is blinking on, on and off while the other flashes on, off, on. This indicates there could be an issue with your furnace’s motherboard or wiring. Lanz Furnace and Fireplace can pinpoint the fault and take care of it.
  7. The pair of lights show alternating slow blinks. This means your furnace possibly has a flame problem. There could be a problem with its gas supply, gas valve or ignitor control. Call us at 608-291-3606 for support.
  8. One light flickers slowly while the other stays continuous. This typically means your furnace’s limit switch is experiencing an error. The switch keeps your HVAC system from becoming too warm. Reach out to the specialists at Lanz Furnace and Fireplace for help.

Heater Blower Works But No Heat

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

  • The pair of lights display alternate quick flashes. This indicates your furnace ignitor may not be in working order. This part lights fuel in your HVAC equipment to make warmth and should be repaired by a specialist from Lanz Furnace and Fireplace.

Depend on Us for Skilled Furnace Repair

When you have to have your heating system in working order without delay, trust the specialists at Lanz Furnace and Fireplace. Our pros will take care of the problem right away and have your residence feeling comfortable again soon. Reach out to us at 608-291-3606 or contact us online to schedule an appointment right away.