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

December 06, 2019

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

Its motherboard has twin LED lights that can display a fault code. Based on the issue, your furnace may use continuous or flashing lights.

Though there are certain elementary HVAC fixes you can complete on your own, most services are best taken care of by HVAC technicians. When your heating system won’t turn on or provide heat, reach out to Air Houston Mechanical LLC at 832-777-1521 for skilled furnace repair in Huffman.

Our technicians will quickly pinpoint and handle the problem, even if you don’t use a Lennox furnace. We can fix all brands or models—and get the comfort restored to your home quickly.


What Does the Blinking Light on My Heating System Mean?

Your heater depends on lights to flash code when it requires repairs. It also engages this system to let you know it’s running like it should.

Normal heating consists of:

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

If you notice one light going on and off slowly and the other flashing rapidly, your heater might have a low flame signal. This can occur even when your heating system is running correctly. It indicates the flame sensing rod could have build-up or in the wrong spot on the burner. Reach out to us at 832-777-1521 for assistance.

Here are some of the most common issues for Lennox HVAC systems.

Furnace Won’t Turn On

Here are many of the light patterns you may notice when your heater won’t turn on or keep running. The majority of these problems have to be taken care of by a professional, for instance from Air Houston Mechanical LLC.

  1. The pair of LED lights aren’t lit. This indicates your heating system might not be receiving power. Check the breaker box to make sure the heating system fuse isn’t flipped. You should reset the fuse if it’s in the “off” position. If it instantly trips after a subsequent reset, don’t try to reset it again and contact us at 832-777-1521.
  2. An individual light is stable and the other is blinking slowly. This implies the flame rollout switch is probably open. The part is an important safety device that helps in stopping fires and carbon monoxide. You shouldn’t attempt to handle this issue on your own.
  3. One light is flashing rapidly and the other is blinking slowly. This usually signifies power polarity has been transposed. Your heater may have a wiring error that requires professional support from Air Houston Mechanical LLC.
  4. The pair of lights are flashing slowly. This signifies your heater’s blower motor likely isn’t working. This component distributes heated air from the heating system into your house. We can help in pinpointing what’s causing an issue with this part.
  5. A single light is flashing slowly and the other is blinking rapidly. This signifies your furnace might have low voltage or a short circuit. Reach out to our experts at 832-777-1521 for support.
  6. One light is flickering on, on and off while the other flashes on, off, on. This signifies there may be trouble with your furnace’s motherboard or wiring. Air Houston Mechanical LLC can pinpoint the error and handle it.
  7. Both lights show alternate slow flashes. This signifies your HVAC equipment may have a flame issue. There could be a problem with its gas supply, gas valve or ignitor control. Call us at 832-777-1521 for help.
  8. A single light flickers slowly while the other stays solid. This usually means your HVAC equipment’s limit switch is experiencing an error. The switch keeps your HVAC equipment from getting too hot. Reach out to the professionals at Air Houston Mechanical LLC for support.

Heating System Blower Works But No Warm Air

Here’s what might be broken when you hear your heating system’s blower fan working, but you aren’t getting any heated air.

  • The pair of lights are giving every other rapid blinks. This means your furnace ignitor may be broken. This piece kindles energy in your furnace to create warm air and should be fixed by a professional from Air Houston Mechanical LLC.

Turn to Us for Professional Furnace Repair

When you need to have your furnace in working order fast, turn to the experts at Air Houston Mechanical LLC. Our pros will repair the problem right away and have your house feeling comfortable again soon. Contact us at 832-777-1521 or contact us online to get an appointment now.