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

December 06, 2019

While your Lennox® heating system cannot talk to you, it does have a method to communicate a furnace error.

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

Although there are certain basic heating fixes you can do without an expert, many tasks are best left to the professionals. When your heating system will not turn on or deliver heat, get in touch with Kowalski Heating, Cooling & Plumbing at 724-370-0141 for professional furnace repair in McMurray.

Our experts will rapidly diagnose and repair the breakdown, even if you don’t have a Lennox furnace. We can fix all types or models—and get the warmth restored to your house without delay.

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What Does the Blinking Light on My Furnace Mean?

Your heating system relies on lights to flash code when it isn’t working right. It also works this setup to relay it’s working properly.

Correct heating includes:

  • Simultaneous slow flash—furnace operating correctly.
  • Both lights flash fast—furnace is starting to call for heat.

If you notice a lone light blinking slowly and the other going on and off rapidly, your heating system might be experiencing a low flame signal. This can happen even when your furnace is working correctly. It means the flame sensing rod could have build-up or in the wrong area on the burner. Reach out to us at 724-370-0141 for help.

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

Heating System Won’t Turn On

Here are some of the light patterns you could notice when your furnace will not or keep heating. Most of these issues must be handled by an expert, for instance from Kowalski Heating, Cooling & Plumbing.

  1. The pair of LED lights are off. This means your furnace might not have electricity. Examine the breaker box to make sure the heater fuse has not flipped. Try resetting the fuse if it’s in the “off” spot. If it rapidly flips after a subsequent reset, leave the breaker alone and get in touch with us us at 724-370-0141.
  2. A single light is stable and the other is flickering slowly. This means the flame rollout switch is probably malfunctioning. The part is an important safety tool that aids in avoiding fires and carbon monoxide. You shouldn’t seek to handle this problem on your own.
  3. A single light is flashing fast and the other is flashing slowly. This typically signifies power polarity has been inverted. Your furnace may have a wiring fault that needs specialized assistance from Kowalski Heating, Cooling & Plumbing.
  4. Both lights are blinking slowly. This indicates your heater’s blower motor likely isn’t operating. This piece moves hot air from the furnace into your space. We can aid in pinpointing what’s causing a problem with this part.
  5. An individual light is blinking slowly and the other is flashing rapidly. This means your furnace may have insufficient voltage or a short circuit. Call our professionals at 724-370-0141 for assistance.
  6. One light is flashing on, on and off while the other flashes on, off, on. This signifies there could be an issue with your HVAC system’s motherboard or wiring. Kowalski Heating, Cooling & Plumbing can find the issue and fix it.
  7. Both lights show alternate slow flickers. This indicates your heater likely has a flame issue. There might be an issue with its gas supply, gas valve or ignitor control. Reach out to us at 724-370-0141 for assistance.
  8. A single light flickers slowly while the other is steady. This often means your heating system’s limit switch is open. The switch prevents your heating system from becoming too warm. Get in touch with the pros at Kowalski Heating, Cooling & Plumbing for support.

Furnace Blower Operates But No Warm Air

Here’s what might be at fault when you observe your heating equipment’s blower fan running, but you aren’t getting any heated air.

  • Both lights display alternate quick blinks. This indicates your furnace ignitor might be broken. This component ignites energy in your furnace to produce warmth and should be serviced by an expert from Kowalski Heating, Cooling & Plumbing.

Turn to Us for Skilled Furnace Repair

When you need to get your furnace repaired quickly, turn to the technicians at Kowalski Heating, Cooling & Plumbing. Our technicians will handle the fault promptly and have your rooms feeling cozy again in no time. Call us at 724-370-0141 or contact us online to get an appointment right away.