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

December 06, 2019

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

Its motherboard has double LED lights that can share a fault code. Subject to the issue, your furnace may display continuous or flashing lights.

Though there are a few simple furnace fixes you can take care of on your own, many fixes are best left to experts. When your heating system will not start or give heated air, call J & J Air Conditioning at 254-355-3833 for skilled furnace repair in Eastland.

Our experts will quickly detect and fix the malfunction, even if you don’t use a Lennox heating system. We can repair any brands or models—and get the warmth reintroduced to your house fast.


What Does the Flashing Light on My Heating System Mean?

Your heater uses lights to flash code when it needs to be repaired. It also engages these lights to relay it’s working correctly.

Regular operation involves:

  • Both lights flash slowly—furnace working correctly.
  • Concurrent fast flash—furnace is beginning to call for heat.

If you notice one light blinking slowly and the other blinking quickly, your furnace could have a low flame signal. This can happen even when your heater is running properly. It signifies the flame sensing rod might need to be cleaned or in the incorrect location on the burner. Reach out to us at 254-355-3833 for help.

Here are some of the most common problems for Lennox heating systems.

Heater Will Not Start

Here are some of the light sequences you may notice when your heating system won’t turn on or stay on. The bulk of these problems have to be repaired by an expert, such as one from J & J Air Conditioning.

  1. The pair of LED lights are extinguished. This indicates your heater might not have power. Find the breaker box to make sure the heating system fuse has not tripped. You should reset the fuse if it has moved into the “off” spot. If it promptly flips following a reset, leave the breaker alone and get in touch with us us at 254-355-3833.
  2. One light is unchanging and the other is blinking slowly. This shows the flame rollout switch is possibly not working right. The part is an important safety device that aids in stopping fires and carbon monoxide. You shouldn’t attempt to handle this issue on your own.
  3. A single light is flickering quickly and the other is blinking slowly. This typically signifies power polarity has been reversed. Your furnace might have a wiring issue that needs professional assistance from J & J Air Conditioning.
  4. Both lights are flickering slowly. This means your heater’s blower motor likely isn’t running. This part circulates hot air from the heater into your home. We can help in figuring out what’s causing an issue with this component.
  5. One light is flashing slowly and the other is flickering rapidly. This means your HVAC system could have low voltage or a short circuit. Contact our technicians at 254-355-3833 for assistance.
  6. One light is flickering on, on and off while the other flickers on, off, on. This signifies there could be an issue with your HVAC system’s control board or wiring. J & J Air Conditioning can pinpoint the fault and handle it.
  7. The pair of lights show every other slow flashes. This means your HVAC equipment possibly has a flame problem. There may be an issue with its gas supply, gas valve or ignitor control. Contact us at 254-355-3833 for assistance.
  8. One light blinks slowly while the other remains continuous. This usually means your heating system’s limit switch is experiencing an error. The switch keeps your heating system from becoming too warm. Call the specialists at J & J Air Conditioning for support.

Heater Blower Runs But No Heat

Here’s what could be wrong when you observe your heater’s blower fan on, but you aren’t getting any warm air.

  • The pair of lights display alternating fast flashes. This signifies your furnace ignitor might not be working. This part ignites gas in your furnace to make heat and should be fixed by a technician from J & J Air Conditioning.

Turn to Us for Expert Furnace Repair

When you have to get your heating system fixed quickly, trust the professionals at J & J Air Conditioning. Our techs will repair the problem quickly and have your space feeling comfortable again in no time. Contact us at 254-355-3833 or contact us online to get an appointment today.