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

December 06, 2019

While your Lennox® furnace cannot speak to you, it has a method to tell you about a furnace error.

Its control board has two LED lights that can show a fault code. Based on the problem, your furnace could show continuous or flashing lights.

Though there are a few elementary HVAC repairs you can do yourself, many services are best left to the professionals. When your heater refuses to turn on or provide warmth, call Service Max Heating & Air Conditioning at 360-255-5857 for expert furnace repair in Arlington.

Our specialists will speedily discover and handle the breakdown, even if you don’t own a Lennox heating system. We can fix whichever kinds or configuration—and get the heat returned to your home without delay.


What Does the Flickering Light on My Furnace Mean?

Your heating system uses lights to flash code when it is malfunctioning. It also works this setup to tell you it’s running correctly.

Correct heating consists of:

  • Concurrent slow flash—furnace operating correctly.
  • Both lights flash fast—heating system is initiating the call for heat.

If you realize that a single light going on and off slowly and the other going on and off fast, your furnace may be having a low flame signal. This can occur even when your heater is heating correctly. It means the flame sensing rod may have build-up or in the wrong location on the burner. Reach out to us at 360-255-5857 for support.

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

Heating System Will Not Start

Here are a few of the light sequences you may observe when your heat won’t turn on or keep running. The bulk of these issues have to be handled by a technician, for instance from Service Max Heating & Air Conditioning.

  1. All LED lights aren’t lit. This indicates your heating system might not have electricity. Look at the breaker box to ensure the furnace fuse hasn’t flipped. You should reset the fuse if it is in the “off” spot. If it immediately flips following a reset, don’t touch the breaker and call us at 360-255-5857.
  2. One light is continuous and the other is blinking slowly. This shows the flame rollout switch is may be malfunctioning. The component is a critical safety tool that aids in avoiding fires and carbon monoxide. You shouldn’t seek to repair this fault without professional help.
  3. A single light is flickering fast and the other is flickering slowly. This usually signifies power polarity has been reversed. Your heater may have a wiring fault that needs professional aid from Service Max Heating & Air Conditioning.
  4. All lights are flashing slowly. This indicates your heater’s blower motor probably isn’t operating. This part moves hot air from the furnace into your home. We can help in determining what’s causing a problem with this part.
  5. One light is flashing slowly and the other is blinking quickly. This means your HVAC system might have insufficient voltage or a short circuit. Reach out to our professionals at 360-255-5857 for support.
  6. One light is flashing on, on and off while the other flickers on, off, on. This signifies there might be a fault with your furnace’s control board or wiring. Service Max Heating & Air Conditioning can pinpoint the issue and repair it.
  7. The duo of lights display alternate slow blinks. This indicates your furnace likely has a flame issue. There might be trouble with its gas supply, gas valve or ignitor control. Reach out to us at 360-255-5857 for help.
  8. An individual light blinks slowly while the other is continuous. This often signifies your heater’s limit switch is open. The switch stops your HVAC system from overheating. Call the experts at Service Max Heating & Air Conditioning for assistance.

Heating System Blower Works But No Warmth

Here’s what may be at fault when you hear your heating system’s blower fan working, but you aren’t gaining any warm air.

  • The duo of lights are giving alternate fast flickers. This indicates your furnace ignitor could be broken. This component kindles energy in your HVAC equipment to make warm air and should be repaired by a specialist from Service Max Heating & Air Conditioning.

Turn to Us for Expert Furnace Repair

When you have to have your furnace in working order quickly, depend on the specialists at Service Max Heating & Air Conditioning. Our techs will take care of the issue promptly and have your home feeling relaxing again in no time. Call us at 360-255-5857 or contact us online to schedule an appointment today.