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

December 06, 2019

While your Lennox® heater can’t speak to you, it does have a process to communicate a furnace error.

Its control board has two LED lights that can share a fault code. Based on the failure, your heater might display continuous or flashing lights.

Although there are a few basic HVAC adjustments you can complete without an expert, most services are best taken care of by HVAC technicians. When your heating system refuses to kick on or deliver heat, call Northglenn Heating & Air Conditioning, Inc. at 303-452-4146 for professional furnace repair in Northglenn.

Our experts will quickly discover and repair the malfunction, even if you don’t have a Lennox heater. We can repair any brands or models—and get the comfort returned to your home without delay.


What Does the Blinking Light on My Furnace Mean?

Your heater relies on lights to flash code when it isn’t working right. It also engages this system to tell you it’s operating correctly.

Regular function consists of:

  • Concurrent slow flash—heater working properly.
  • Both lights flash fast—heating system is initiating the call for heat.

If you see a lone light flashing slowly and the other blinking rapidly, your heating system might have a low flame signal. This can take place even when your heating system is working properly. It indicates the flame sensing rod could be dirty or in the bad area on the burner. Contact us at 303-452-4146 for assistance.

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

Furnace Will Not Kick On

Here are some of the light sequences you could notice when your heating system will not or stay on. The majority of these issues must be repaired by an expert, such as one from Northglenn Heating & Air Conditioning, Inc..

  1. Both LED lights aren’t lit. This indicates your heater might not be receiving power. Check the breaker box to make sure the heater fuse is not triggered. You should reset the fuse if it has moved into the “off” area. If it instantly turns off after a subsequent reset, leave the breaker alone and get in touch with us us at 303-452-4146.
  2. An individual light is unchanging and the other is blinking slowly. This signifies the flame rollout switch is probably malfunctioning. The component is an essential safety guard that assists in stopping fires and carbon monoxide. You shouldn’t seek to handle this fault yourself.
  3. One light is blinking rapidly and the other is flashing slowly. This often means power polarity has been inverted. Your heater might have a wiring error that requires expert support from Northglenn Heating & Air Conditioning, Inc..
  4. All lights are flashing slowly. This means your heating system’s blower motor likely isn’t operating. This component sends warm air from the furnace into your residence. We can aid in determining what’s wrong with this piece.
  5. A single light is blinking slowly and the other is flickering fast. This signifies your heater might have low voltage or a short circuit. Get in touch with our technicians at 303-452-4146 for support.
  6. One light is blinking on, on and off while the other blinks on, off, on. This indicates there may be trouble with your HVAC system’s control board or wiring. Northglenn Heating & Air Conditioning, Inc. can pinpoint the issue and fix it.
  7. The duo of lights show alternate slow blinks. This indicates your furnace possibly has a flame issue. There may be trouble with its gas supply, gas valve or ignitor control. Call us at 303-452-4146 for help.
  8. One light flashes slowly while the other is continuous. This typically means your furnace’s limit switch is open. The switch stops your HVAC equipment from becoming too warm. Get in touch with the pros at Northglenn Heating & Air Conditioning, Inc. for support.

Heater Blower Operates But No Warm Air

Here’s what might be wrong when you notice your heater’s blower fan running, but you aren’t getting any heated air.

  • The duo of lights are giving alternate fast blinks. This indicates your furnace ignitor may not be in working order. This part lights fuel in your furnace to produce warmth and should be repaired by an expert from Northglenn Heating & Air Conditioning, Inc..

Depend on Us for Expert Furnace Repair

When you need to get your heating system fixed quickly, trust the technicians at Northglenn Heating & Air Conditioning, Inc.. Our techs will handle the fault promptly and have your rooms feeling comfortable again in a short time. Reach out to us at 303-452-4146 or contact us online to schedule an appointment today.