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

December 06, 2019

While your Lennox® heating system isn’t able to speak to you, it does have a process to tell you about a furnace error.

Its motherboard has twin LED lights that can share a fault code. Depending on the failure, your furnace could show continuous or flashing lights.

Though there are some simple HVAC repairs you can do on your own, most fixes are best taken care of by HVAC technicians. When your heating system will not start or give warm air, reach out to Bishop Heating & Air Conditioning at 760-784-9034 for experienced furnace repair in Bishop.

Our specialists will swiftly determine and handle the issue, even if you don’t use a Lennox furnace. We can fix whichever types or models—and get the warmth returned to your house without delay.


What Does the Flashing Light on My Heating System Mean?

Your heating system depends on lights to flash code when it requires repairs. It also works these lights to tell you it’s operating correctly.

Normal heating includes:

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

If you see a solitary light going on and off slowly and the other blinking rapidly, your heating system may have a low flame signal. This can happen even when your furnace is operating correctly. It means the flame sensing rod may have build-up or in the bad spot on the burner. Contact us at 760-784-9034 for support.

Here are several other of the most common faults for Lennox heaters.

Heating System Won’t Turn On

Here are many of the light patterns you may observe when your heater refuses to or keep heating. Most of these issues need to be handled by a specialist, such as one from Bishop Heating & Air Conditioning.

  1. Both LED lights aren’t lit. This indicates your furnace might not have electricity. Check the breaker box to confirm the heater fuse isn’t tripped. Try resetting the fuse if it’s in the “off” position. If it promptly trips following a reset, leave the breaker alone and call us at 760-784-9034.
  2. A single light is unchanging and the other is flickering slowly. This means the flame rollout switch is likely open. The part is a critical safety tool that aids in avoiding fires and carbon monoxide. You shouldn’t attempt to repair this malfunction yourself.
  3. A single light is flickering fast and the other is blinking slowly. This likely indicates power polarity has been transposed. Your heater may have a wiring issue that requires specialized help from Bishop Heating & Air Conditioning.
  4. The duo of lights are flashing slowly. This indicates your furnace’s blower motor probably isn’t running. This component distributes heated air from the HVAC system into your house. We can aid in pinpointing what’s causing an issue with this piece.
  5. One light is flickering slowly and the other is blinking fast. This indicates your heating system might have insufficient voltage or a short circuit. Get in touch with our technicians at 760-784-9034 for support.
  6. One light is blinking on, on and off while the other blinks on, off, on. This means there might be an error with your furnace’s control panel or wiring. Bishop Heating & Air Conditioning can find the issue and fix it.
  7. The pair of lights display alternate slow blinks. This means your heater likely has a flame problem. There may be trouble with its gas supply, gas valve or ignitor control. Get in touch with us at 760-784-9034 for support.
  8. An individual light flashes slowly while the other remains solid. This typically indicates your heating system’s limit switch is experiencing an error. The switch prevents your HVAC system from getting too hot. Reach out to the specialists at Bishop Heating & Air Conditioning for support.

Heating System Blower Runs But No Warm Air

Here’s what might be broken when you notice your heating system’s blower fan on, but you aren’t receiving any heat.

  • Both lights are giving alternate rapid blinks. This indicates your furnace ignitor could be broken. This piece ignites fuel in your furnace to make warm air and should be fixed by a specialist from Bishop Heating & Air Conditioning.

Depend on Us for Professional Furnace Repair

When you have to have your furnace in working order without delay, trust the technicians at Bishop Heating & Air Conditioning. Our pros will repair the fault right away and have your house feeling comfortable again in a short time. Get in touch with us at 760-784-9034 or contact us online to request an appointment now.