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

December 06, 2019

While your Lennox® HVAC equipment can’t talk to you, it has a way to get your attention when there’s a furnace error.

Its control board has twin LED lights that can display a fault code. Based on the malfunction, your heater could display continuous or flashing lights.

Though there are various elementary furnace fixes you can finish on your own, most fixes are best left to the professionals. When your heating system won’t start or provide heat, call Aggressive Mechanical at 732-806-5536 for skilled furnace repair in Neptune City.

Our experts will rapidly identify and fix the problem, even if you don’t have a Lennox heating system. We can service all types or models—and get the heat reintroduced to your residence without delay.


What Does the Blinking Light on My Heater Mean?

Your heating system relies on lights to flash code when it isn’t working right. It also works this system to tell you it’s running correctly.

Normal function involves:

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

If you see a solitary light flashing slowly and the other blinking fast, your heating system could be experiencing a low flame signal. This can take place even when your heating system is heating correctly. It signifies the flame sensing rod might have build-up or in the wrong location on the burner. Call us at 732-806-5536 for support.

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

Heating System Will Not Start

Here are many of the light patterns you might see when your heater will not or stay on. The majority of these problems must be handled by a professional, like one from Aggressive Mechanical.

  1. The pair of LED lights are extinguished. This indicates your HVAC system might not have electricity. Look at the breaker box to ensure the furnace fuse has not tripped. Try resetting the fuse if it has moved into the “off” spot. If it immediately trips following a reset, don’t try to reset it again and contact us at 732-806-5536.
  2. One light is continuous and the other is flickering slowly. This implies the flame rollout switch is possibly open. The component is a critical safety mechanism that aids in stopping fires and carbon monoxide. You shouldn’t attempt to fix this malfunction without professional help.
  3. A single light is flashing rapidly and the other is flashing slowly. This likely indicates power polarity has been transposed. Your furnace may have a wiring error that calls for professional aid from Aggressive Mechanical.
  4. Both lights are flickering slowly. This signifies your heating system’s blower motor probably isn’t running. This piece circulates heated air from the furnace into your residence. We can help in determining what’s wrong with this piece.
  5. A single light is flickering slowly and the other is flickering fast. This indicates your heater might have low voltage or a short circuit. Contact our technicians at 732-806-5536 for support.
  6. One light is flickering on, on and off while the other flickers on, off, on. This indicates there could be a malfunction with your heater’s control board or wiring. Aggressive Mechanical can locate the error and fix it.
  7. Both lights show alternate slow blinks. This means your heating system likely has a flame issue. There might be a problem with its gas supply, gas valve or ignitor control. Reach out to us at 732-806-5536 for assistance.
  8. A single light flickers slowly while the other stays continuous. This often means your HVAC equipment’s limit switch is experiencing an error. The switch stops your HVAC system from overheating. Get in touch with the experts at Aggressive Mechanical for support.

Heater Blower Operates But No Warm Air

Here’s what might be wrong when you hear your furnace’s blower fan running, but you aren’t receiving any heat.

  • Both lights are giving alternate rapid flashes. This means your furnace ignitor might not be working. This piece ignites fuel in your heater to create warm air and should be repaired by an expert from Aggressive Mechanical.

Depend on Us for Expert Furnace Repair

When you have to get your heater fixed without delay, trust the experts at Aggressive Mechanical. Our techs will handle the problem promptly and have your house feeling cozy again in a short time. Call us at 732-806-5536 or contact us online to get an appointment right away.