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

December 06, 2019

While your Lennox® heating system cannot speak to you, it possesses a procedure to communicate a furnace error.

Its motherboard has a set of LED lights that can display a fault code. Depending on the issue, your furnace could use continuous or flashing lights.

While there are various simple furnace adjustments you can take care of yourself, most tasks are best handled by the professionals. When your heating system will not turn on or put out heat, call WM J Kraus & Son at 319-229-2318 for skilled furnace repair in Keokuk.

Our specialists will swiftly identify and repair the failure, even if you don’t own a Lennox heater. We can repair any brands or makes—and get the comfort returned to your house quickly.


What Does the Blinking Light on My Furnace Mean?

Your furnace relies on lights to flash code when it is malfunctioning. It also works this system to relay it’s operating correctly.

Regular function involves:

  • Both lights flash slowly—heater heating properly.
  • Simultaneous fast flash—furnace is initiating the call for heat.

If you notice one light flashing slowly and the other blinking fast, your heater may be having a low flame signal. This can take place even when your heating system is working like it should. It means the flame sensing rod may have build-up or in the wrong spot on the burner. Call us at 319-229-2318 for help.

Here are several other of the most typical problems for Lennox furnaces.

Heater Will Not Turn On

Here are many of the light sequences you may notice when your furnace won’t turn on or keep running. The majority of these issues must be fixed by a specialist, like one from WM J Kraus & Son.

  1. The duo of LED lights aren’t lit. This means your furnace might not have electricity. Find the breaker box to confirm the heating system fuse has not flipped. You should reset the fuse if it’s in the “off” spot. If it promptly flips after a subsequent reset, don’t touch the breaker and contact us at 319-229-2318.
  2. A single light is solid and the other is flickering slowly. This means the flame rollout switch is may be open. The switch is an important safety guard that helps in avoiding fires and carbon monoxide. You shouldn’t seek to repair this problem yourself.
  3. An individual light is flashing quickly and the other is flickering slowly. This often means power polarity has been reversed. Your heating system might have a wiring issue that calls for professional assistance from WM J Kraus & Son.
  4. The pair of lights are blinking slowly. This means your heater’s blower motor probably isn’t working. This component circulates heated air from the furnace into your house. We can aid in figuring out what’s wrong with this piece.
  5. An individual light is blinking slowly and the other is blinking quickly. This indicates your furnace might have low voltage or a short circuit. Contact our experts at 319-229-2318 for assistance.
  6. One light is flickering on, on and off while the other blinks on, off, on. This indicates there might be a problem with your HVAC system’s motherboard or wiring. WM J Kraus & Son can pinpoint the issue and take care of it.
  7. Both lights show alternate slow flickers. This indicates your furnace may have a flame error. There may be a problem with its gas supply, gas valve or ignitor control. Contact us at 319-229-2318 for support.
  8. A single light blinks slowly while the other is steady. This usually indicates your furnace’s limit switch is malfunctioning. The switch prevents your HVAC equipment from overheating. Contact the professionals at WM J Kraus & Son for assistance.

Heating System Blower Operates But No Warm Air

Here’s what could be broken when you observe your heating system’s blower fan working, but you aren’t receiving any warm air.

  • The pair of lights are giving alternate fast blinks. This means your furnace ignitor might not be in working order. This piece ignites energy in your HVAC equipment to produce heat and should be serviced by a professional from WM J Kraus & Son.

Turn to Us for Skilled Furnace Repair

When you have to get your heater in working order quickly, trust the technicians at WM J Kraus & Son. Our pros will repair the fault right away and have your space feeling relaxing again in no time. Contact us at 319-229-2318 or contact us online to schedule an appointment now.