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

December 06, 2019

While your Lennox® heater isn’t able to chat with you, it possesses a way to get your attention when there’s a furnace error.

Its control board has twin LED lights that can share a fault code. Subject to the failure, your heating system may show continuous or flashing lights.

Although there are various basic HVAC adjustments you can complete on your own, the majority of repairs are best left to the professionals. When your furnace won’t kick on or provide heat, call Clean Air HVAC at 925-233-6238 for skilled furnace repair in Pacheco.

Our technicians will swiftly identify and take care of the failure, even if you don’t own a Lennox heater. We can repair all types or models—and get the comfort returned to your house without delay.


What Does the Flashing Light on My Furnace Mean?

Your heating system uses lights to flash code when it isn’t working right. It also engages this system to tell you it’s working correctly.

Correct heating consists of:

  • Simultaneous slow flash—heating system running like it should.
  • Both lights flash fast—heater is initiating the call for heat.

If you realize that a lone light blinking slowly and the other blinking fast, your furnace could be experiencing a low flame signal. This can occur even when your furnace is running correctly. It indicates the flame sensing rod could be dirty or in the bad area on the burner. Reach out to us at 925-233-6238 for support.

Here are some of the most typical errors for Lennox HVAC systems.

Furnace Will Not Turn On

Here are some of the light arrangements you could observe when your heating system refuses to or stay on. Most of these errors must be repaired by a technician, like one from Clean Air HVAC.

  1. The pair of LED lights are off. This means your heater might not have power. Examine the breaker box to confirm the heater fuse hasn’t tripped. You should reset the fuse if it’s in the “off” position. If it rapidly trips after you reset it, don’t touch the breaker and contact us at 925-233-6238.
  2. A single light is continuous and the other is flashing slowly. This signifies the flame rollout switch is possibly malfunctioning. The component is an essential safety guard that aids in preventing fires and carbon monoxide. You shouldn’t seek to take care of this fault without professional help.
  3. An individual light is flashing quickly and the other is blinking slowly. This likely means power polarity has been inverted. Your heating system might have a wiring error that calls for expert help from Clean Air HVAC.
  4. Both lights are flickering slowly. This indicates your furnace’s blower motor possibly isn’t operating. This piece distributes warm air from the heating system into your residence. We can help in pinpointing what’s wrong with this piece.
  5. One light is flickering slowly and the other is blinking fast. This means your furnace might have not enough voltage or a short circuit. Contact our specialists at 925-233-6238 for support.
  6. One light is blinking on, on and off while the other flashes on, off, on. This indicates there might be a fault with your furnace’s control board or wiring. Clean Air HVAC can find the issue and repair it.
  7. The pair of lights display every other slow blinks. This signifies your HVAC equipment may have a flame failure. There might be trouble with its gas supply, gas valve or ignitor control. Contact us at 925-233-6238 for support.
  8. An individual light flickers slowly while the other stays continuous. This often means your HVAC system’s limit switch is not working. The switch keeps your HVAC equipment from overheating. Call the professionals at Clean Air HVAC for support.

Heater Blower Works But No Warm Air

Here’s what may be at fault when you notice your heater’s blower fan running, but you aren’t gaining any heat.

  • The pair of lights are showing alternating rapid flashes. This indicates your furnace ignitor might not be working. This component kindles energy in your HVAC equipment to create warmth and should be fixed by an expert from Clean Air HVAC.

Turn to Us for Skilled Furnace Repair

When you need to get your HVAC equipment in working order fast, trust the professionals at Clean Air HVAC. Our techs will handle the fault promptly and have your rooms feeling relaxing again soon. Get in touch with us at 925-233-6238 or contact us online to schedule an appointment right away.