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

December 06, 2019

While your Lennox® HVAC equipment cannot talk to you, it does have a way to tell you about a furnace error.

Its control panel has two LED lights that can show a fault code. Depending on the fault, your heating system could use continuous or flashing lights.

While there are various simple HVAC fixes you can do on your own, the majority of tasks are best handled by the professionals. When your heater refuses to kick on or provide heated air, contact Temperature Doctors Heating & Cooling, Inc at (815)914-6197 for professional furnace repair in Rockford.

Our specialists will quickly discover and fix the problem, even if you don’t have a Lennox heating system. We can repair all brands or configuration—and get the heat restored to your house fast.


What Does the Blinking Light on My Heater Mean?

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

Normal operation involves:

  • Concurrent slow flash—furnace heating correctly.
  • Both lights flash fast—heating system is beginning to call for heat.

If you realize that a lone light going on and off slowly and the other going on and off fast, your furnace may be having a low flame signal. This can happen even when your heater is running like it should. It means the flame sensing rod could need to be cleaned or in the incorrect spot on the burner. Call us at (815)914-6197 for assistance.

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

Furnace Won’t Start

Here are some of the light sequences you could notice when your heater refuses to or keep heating. Most of these issues must be handled by a specialist, for instance from Temperature Doctors Heating & Cooling, Inc.

  1. The pair of LED lights are off. This signifies your heater might not have power. Examine the breaker box to make sure the heater fuse has not tripped. Try resetting the fuse if it’s in the “off” spot. If it immediately trips after you reset it, don’t touch the breaker and get in touch with us us at (815)914-6197.
  2. One light is continuous and the other is blinking slowly. This implies the flame rollout switch is may be malfunctioning. The switch is an essential safety device that aids in stopping fires and carbon monoxide. You shouldn’t attempt to repair this problem yourself.
  3. One light is flickering rapidly and the other is flickering slowly. This likely means power polarity has been inverted. Your heater may have a wiring issue that requires expert help from Temperature Doctors Heating & Cooling, Inc.
  4. The pair of lights are flickering slowly. This means your heating system’s blower motor probably isn’t operating. This part moves heated air from the HVAC system into your space. We can assist in figuring out what’s causing an issue with this part.
  5. An individual light is flickering slowly and the other is flashing fast. This signifies your heater could have not enough voltage or a short circuit. Contact our specialists at (815)914-6197 for help.
  6. One light is flickering on, on and off while the other blinks on, off, on. This indicates there may be trouble with your heating system’s control panel or wiring. Temperature Doctors Heating & Cooling, Inc can locate the error and fix it.
  7. Both lights are using every other slow flickers. This signifies your heater likely has a flame failure. There could be trouble with its gas supply, gas valve or ignitor control. Contact us at (815)914-6197 for support.
  8. One light flashes slowly while the other stays continuous. This often signifies your heater’s limit switch is malfunctioning. The switch keeps your HVAC system from becoming too warm. Get in touch with the experts at Temperature Doctors Heating & Cooling, Inc for support.

Heating System Blower Works But No Heat

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

  • Both lights display alternating fast blinks. This signifies your furnace ignitor might not be in working order. This piece ignites fuel in your heater to produce heat and should be serviced by a technician from Temperature Doctors Heating & Cooling, Inc.

Trust Us for Expert Furnace Repair

When you need to have your furnace repaired without delay, turn to the experts at Temperature Doctors Heating & Cooling, Inc. Our techs will take care of the error quickly and have your house feeling cozy again in a short time. Get in touch with us at (815)914-6197 or contact us online to schedule an appointment today.