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

December 06, 2019

While your Lennox® heating system isn’t able to chat with you, it does have a method to get your attention when there’s a furnace error.

Its control board has a set of LED lights that can share a fault code. Based on the problem, your heating system could display continuous or flashing lights.

Although there are certain elementary furnace adjustments you can complete without an expert, most tasks are best left to HVAC technicians. When your heating system won’t start or put out heated air, contact Miller Climate Control LLC at 512-937-2001 for experienced furnace repair in Georgetown.

Our experts will rapidly diagnose and take care of the fault, even if you don’t own a Lennox furnace. We can repair all kinds or models—and get the warmth returned to your house quickly.


What Does the Blinking Light on My Heater Mean?

Your furnace relies on lights to flash code when it is malfunctioning. It also engages this system to tell you it’s working correctly.

Normal operation includes:

  • Simultaneous slow flash—furnace running properly.
  • Concurrent fast flash—heating system is initiating the call for heat.

If you realize that a lone light blinking slowly and the other blinking rapidly, your heating system may have a low flame signal. This can happen even when your heater is working properly. It signifies the flame sensing rod could have build-up or in the incorrect location on the burner. Contact us at 512-937-2001 for assistance.

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

Heater Won’t Kick On

Here are some of the light sequences you may see when your heat won’t turn on or stay on. The majority of these errors need to be handled by a technician, for instance from Miller Climate Control LLC.

  1. Both LED lights are extinguished. This indicates your HVAC system might not have power. Look at the breaker box to confirm the furnace fuse hasn’t tripped. Attempt to reset the fuse if it is in the “off” spot. If it immediately turns off following a reset, don’t try to reset it again and contact us at 512-937-2001.
  2. A single light is continuous and the other is flickering slowly. This signifies the flame rollout switch is probably open. The component is an important safety device that assists in stopping fires and carbon monoxide. You shouldn’t try to take care of this fault on your own.
  3. A single light is flashing rapidly and the other is flashing slowly. This typically signifies power polarity has been inverted. Your furnace might have a wiring error that needs expert help from Miller Climate Control LLC.
  4. The pair of lights are flashing slowly. This means your furnace’s blower motor probably isn’t operating. This component distributes warm air from the furnace into your house. We can assist in figuring out what’s causing an issue with this piece.
  5. A single light is flickering slowly and the other is flashing quickly. This signifies your furnace could have low voltage or a short circuit. Call our technicians at 512-937-2001 for assistance.
  6. One light is flickering on, on and off while the other flashes on, off, on. This indicates there could be an error with your heater’s motherboard or wiring. Miller Climate Control LLC can find the problem and take care of it.
  7. The duo of lights show alternate slow flashes. This signifies your HVAC system likely has a flame error. There may be trouble with its gas supply, gas valve or ignitor control. Get in touch with us at 512-937-2001 for help.
  8. One light flashes slowly while the other stays continuous. This typically indicates your heating system’s limit switch is not working. The switch prevents your HVAC equipment from becoming too warm. Get in touch with the professionals at Miller Climate Control LLC for support.

Furnace Blower Runs But No Warm Air

Here’s what could be at fault when you notice your furnace’s blower fan on, but you aren’t gaining any heated air.

  • Both lights display alternating quick flickers. This signifies your furnace ignitor might not be in working order. This component lights fuel in your heater to produce warm air and should be serviced by a professional from Miller Climate Control LLC.

Trust Us for Skilled Furnace Repair

When you need to get your heating system fixed fast, depend on the technicians at Miller Climate Control LLC. Our pros will fix the problem promptly and have your rooms feeling relaxing again soon. Reach out to us at 512-937-2001 or contact us online to schedule an appointment right away.