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

December 06, 2019

While your Lennox® heating system cannot chat with you, it does have a way to communicate a furnace error.

Its motherboard has a set of LED lights that can display a fault code. Based on the fault, your heater may use continuous or flashing lights.

Although there are some elementary heating adjustments you can complete yourself, many tasks are best left to the professionals. When your furnace won’t kick on or provide heated air, call Lakeside Heating & Air at 509-284-4265 for skilled furnace repair in Chelan and Wenatchee.

Our technicians will quickly detect and take care of the failure, even if you don’t have a Lennox furnace. We can repair any kinds or configuration—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 needs to be repaired. It also works this setup to let you know it’s operating correctly.

Regular operation involves:

  • Concurrent slow flash—heating system working like it should.
  • Both lights flash fast—furnace is starting to call for heat.

If you notice one light blinking slowly and the other blinking rapidly, your heater may be experiencing a low flame signal. This can happen even when your heater is running correctly. It indicates the flame sensing rod may have build-up or in the wrong spot on the burner. Reach out to us at 509-284-4265 for support.

Here are a few other of the most common faults for Lennox heaters.

Heating System Will Not Turn On

Here are a few of the light patterns you might notice when your heat refuses to or keep running. The bulk of these issues must be repaired by a technician, such as one from Lakeside Heating & Air.

  1. The pair of LED lights are off. This signifies your furnace might not be receiving power. Find the breaker box to confirm the heater fuse isn’t triggered. You should reset the fuse if it has moved into the “off” spot. If it rapidly turns off following a reset, leave the breaker alone and contact us at 509-284-4265.
  2. One light is stable and the other is flickering slowly. This signifies the flame rollout switch is likely open. The switch is an important safety mechanism that aids in stopping fires and carbon monoxide. You shouldn’t attempt to repair this issue yourself.
  3. A single light is flickering fast and the other is flashing slowly. This typically signifies power polarity has been inverted. Your furnace could have a wiring problem that calls for expert support from Lakeside Heating & Air.
  4. The duo of lights are blinking slowly. This signifies your furnace’s blower motor likely isn’t operating. This part distributes hot air from the furnace into your residence. We can assist in determining what’s causing an issue with this piece.
  5. One light is flashing slowly and the other is flashing quickly. This signifies your heating system may have insufficient voltage or a short circuit. Contact our technicians at 509-284-4265 for support.
  6. One light is flashing on, on and off while the other flashes on, off, on. This means there could be a malfunction with your furnace’s control panel or wiring. Lakeside Heating & Air can determine the issue and fix it.
  7. The duo of lights display alternating slow blinks. This indicates your furnace may have a flame failure. There could be a problem with its gas supply, gas valve or ignitor control. Get in touch with us at 509-284-4265 for support.
  8. One light blinks slowly while the other remains steady. This typically indicates your HVAC system’s limit switch is open. The switch prevents your HVAC system from getting too hot. Contact the experts at Lakeside Heating & Air for assistance.

Heating System Blower Works But No Warm Air

Here’s what could be at fault when you observe your heating equipment’s blower fan running, but you aren’t receiving any heat.

  • Both lights are giving alternating quick blinks. This signifies your furnace ignitor could be broken. This component lights fuel in your furnace to make heat and should be repaired by an expert from Lakeside Heating & Air.

Turn to Us for Skilled Furnace Repair

When you have to have your heating system fixed quickly, trust the experts at Lakeside Heating & Air. Our pros will fix the issue promptly and have your residence feeling comfortable again in a short time. Contact us at 509-284-4265 or contact us online to schedule an appointment right away.