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

December 06, 2019

While your Lennox® furnace can’t speak to you, it possesses a method to tell you about a furnace error.

Its control panel has double LED lights that can show a fault code. Subject to the problem, your heating system might use steady or flashing lights.

Although there are various basic furnace fixes you can finish yourself, most repairs are best left to experts. When your heater will not turn on or deliver heated air, get in touch with Precision Mechanical at 605-206-3766 for experienced furnace repair in Rapid City.

Our technicians will quickly detect and handle the problem, even if you don’t have a Lennox furnace. We can service whichever brands or models—and get the heat returned to your house without delay.


What Does the Flashing Light on My Furnace Mean?

Your heater depends on lights to flash code when it needs to be repaired. It also works this system to relay it’s heating like it should.

Correct function consists of:

  • Both lights flash slowly—heating system working like it should.
  • Simultaneous fast flash—heating system is beginning to call for heat.

If you see a single light blinking slowly and the other flashing quickly, your heater may be having a low flame signal. This can take place even when your heater is operating properly. It indicates the flame sensing rod might need to be cleaned or in the incorrect location on the burner. Call us at 605-206-3766 for assistance.

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

Heating System Won’t Kick On

Here are many of the light arrangements you may notice when your heat refuses to or keep operating. Most of these problems need to be taken care of by an expert, like one from Precision Mechanical.

  1. Both LED lights are off. This means your HVAC system might not be receiving power. Check the breaker box to make sure the heating system fuse isn’t flipped. Try resetting the fuse if it is in the “off” area. If it rapidly trips after you reset it, don’t try to reset it again and contact us at 605-206-3766.
  2. One light is stable and the other is flickering slowly. This means the flame rollout switch is possibly open. The switch is an important safety mechanism that aids in avoiding fires and carbon monoxide. You shouldn’t attempt to fix this problem on your own.
  3. A single light is blinking fast and the other is blinking slowly. This often signifies power polarity has been reversed. Your furnace may have a wiring error that requires specialized aid from Precision Mechanical.
  4. The duo of lights are blinking slowly. This indicates your heater’s blower motor likely isn’t operating. This part moves heated air from the HVAC system into your house. We can assist in determining what’s causing a problem with this piece.
  5. An individual light is blinking slowly and the other is flickering rapidly. This signifies your furnace may have insufficient voltage or a short circuit. Call our experts at 605-206-3766 for help.
  6. One light is flickering on, on and off while the other flickers on, off, on. This means there may be a fault with your HVAC system’s control panel or wiring. Precision Mechanical can pinpoint the problem and handle it.
  7. The pair of lights are using alternating slow blinks. This signifies your HVAC equipment likely has a flame failure. There could be trouble with its gas supply, gas valve or ignitor control. Contact us at 605-206-3766 for help.
  8. An individual light flickers slowly while the other is steady. This typically signifies your HVAC system’s limit switch is not working. The switch prevents your heater from getting too hot. Get in touch with the experts at Precision Mechanical for help.

Furnace Blower Runs But No Warmth

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

  • Both lights are showing alternating fast blinks. This means your furnace ignitor may be broken. This piece lights energy in your heater to make heat and should be fixed by an expert from Precision Mechanical.

Trust Us for Skilled Furnace Repair

When you have to get your heater repaired quickly, turn to the specialists at Precision Mechanical. Our techs will fix the issue without delay and have your home feeling relaxing again in a short time. Reach out to us at 605-206-3766 or contact us online to request an appointment today.