Top Lennox® Furnace Error Codes (and What They Mean)

December 06, 2019

While your Lennox® heating system can’t speak to you, it has a method to tell you about a furnace error.

Its control board has a set of LED lights that can display a fault code. Subject to the failure, your furnace might use steady or flashing lights.

Though there are some basic heating fixes you can finish yourself, many fixes are best handled by experts. When your heating system won’t start or put out warmth, call GV Heating & Air at 763-535-2000 for professional furnace repair in Crystal and Twin Cities.

Our technicians will rapidly detect and take care of the malfunction, even if you don’t have a Lennox heating system. We can service whichever kinds or makes—and get the heat restored to your residence fast.


What Does the Flashing Light on My Furnace Mean?

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

Normal operation includes:

  • Concurrent slow flash—heater working like it should.
  • Simultaneous fast flash—heating system is beginning to call for heat.

If you see a lone light flashing slowly and the other flashing rapidly, your furnace might be experiencing a low flame signal. This can take place even when your heater is heating correctly. It means the flame sensing rod may need to be cleaned or in the bad spot on the burner. Contact us at 763-535-2000 for help.

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

Heating System Will Not Start

Here are many of the light patterns you could see when your furnace will not or keep operating. The majority of these problems need to be handled by a specialist, for instance from GV Heating & Air.

  1. The pair of LED lights are off. This signifies your heater might not be receiving power. Look at the breaker box to confirm the heating system fuse hasn’t flipped. You should reset the fuse if it has moved into the “off” position. If it instantly turns off after a subsequent reset, don’t touch the breaker and contact us at 763-535-2000.
  2. A single light is unchanging and the other is flashing slowly. This signifies the flame rollout switch is probably malfunctioning. The component is a critical safety mechanism that helps in stopping fires and carbon monoxide. You shouldn’t try to fix this malfunction yourself.
  3. One light is flashing quickly and the other is flashing slowly. This often indicates power polarity has been inverted. Your heating system may have a wiring fault that requires specialized support from GV Heating & Air.
  4. Both lights are flashing slowly. This indicates your furnace’s blower motor probably isn’t working. This component moves heated air from the heating system into your rooms. We can assist in determining what’s causing an issue with this component.
  5. One light is blinking slowly and the other is blinking fast. This means your heating system could have low voltage or a short circuit. Reach out to our specialists at 763-535-2000 for assistance.
  6. One light is flickering on, on and off while the other flickers on, off, on. This means there may be a malfunction with your HVAC system’s control panel or wiring. GV Heating & Air can pinpoint the issue and take care of it.
  7. The pair of lights display alternating slow blinks. This indicates your furnace may have a flame issue. There could be an issue with its gas supply, gas valve or ignitor control. Get in touch with us at 763-535-2000 for help.
  8. One light flashes slowly while the other stays solid. This often signifies your HVAC system’s limit switch is malfunctioning. The switch stops your heating system from becoming too warm. Reach out to the pros at GV Heating & Air for assistance.

Furnace Blower Operates But No Warm Air

Here’s what may be broken when you observe your heater’s blower fan on, but you aren’t getting any warm air.

  • The pair of lights are giving alternating fast flickers. This means your furnace ignitor could not be working. This part lights gas in your furnace to create heat and should be serviced by a specialist from GV Heating & Air.

Trust Us for Skilled Furnace Repair

When you have to get your heater fixed quickly, turn to the specialists at GV Heating & Air. Our techs will repair the problem right away and have your house feeling relaxing again soon. Reach out to us at 763-535-2000 or contact us online to request an appointment today.