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

December 06, 2019

While your Lennox® HVAC equipment can’t talk to you, it has a process to get your attention when there’s a furnace error.

Its motherboard has a set of LED lights that can display a fault code. Based on the issue, your heating system may display steady or flashing lights.

While there are various basic HVAC adjustments you can finish on your own, most repairs are best taken care of by the professionals. When your heating system won’t kick on or put out warm air, reach out to Honke Heating & AC at 503-663-8033 for experienced furnace repair in Gresham.

Our specialists will speedily determine and repair the problem, even if you don’t use a Lennox furnace. We can service all types or models—and get the comfort reintroduced to your residence without delay.


What Does the Flickering Light on My Heater Mean?

Your heating system depends on lights to flash code when it needs to be repaired. It also works these lights to let you know it’s operating correctly.

Regular operation consists of:

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

If you see one light flashing slowly and the other flashing fast, your furnace may be having a low flame signal. This can happen even when your heating system is operating like it should. It indicates the flame sensing rod may be dirty or in the incorrect location on the burner. Contact us at 503-663-8033 for assistance.

Here are some of the most routine faults for Lennox furnaces.

Furnace Will Not Turn On

Here are some of the light sequences you could see when your heater won’t turn on or stay on. The bulk of these problems must be taken care of by a specialist, for instance from Honke Heating & AC.

  1. The duo of LED lights are extinguished. This indicates your HVAC system might not have electricity. Check the breaker box to confirm the furnace fuse has not triggered. Try resetting the fuse if it has moved into the “off” position. If it immediately trips following a reset, don’t touch the breaker and contact us at 503-663-8033.
  2. An individual light is continuous and the other is flickering slowly. This means the flame rollout switch is probably not working right. The component is an important safety device that assists in stopping fires and carbon monoxide. You shouldn’t seek to handle this malfunction without professional help.
  3. One light is blinking rapidly and the other is flickering slowly. This often means power polarity has been transposed. Your heater might have a wiring error that calls for professional aid from Honke Heating & AC.
  4. The pair of lights are flashing slowly. This indicates your heater’s blower motor likely isn’t operating. This piece circulates hot air from the furnace into your residence. We can aid in pinpointing what’s wrong with this part.
  5. One light is flashing slowly and the other is flickering quickly. This indicates your heater might have insufficient voltage or a short circuit. Call our professionals at 503-663-8033 for assistance.
  6. One light is flickering on, on and off while the other blinks on, off, on. This signifies there may be trouble with your furnace’s control board or wiring. Honke Heating & AC can find the fault and fix it.
  7. The pair of lights are using alternate slow flickers. This signifies your heating system possibly has a flame failure. There might be trouble with its gas supply, gas valve or ignitor control. Contact us at 503-663-8033 for assistance.
  8. An individual light blinks slowly while the other remains continuous. This often means your heater’s limit switch is open. The switch stops your furnace from getting too hot. Call the pros at Honke Heating & AC for help.

Heater Blower Runs But No Warm Air

Here’s what may be at fault when you notice your furnace’s blower fan working, but you aren’t receiving any warmth.

  • Both lights are giving alternating quick flickers. This means your furnace ignitor could not be working. This part ignites energy in your furnace to produce warm air and should be serviced by an expert from Honke Heating & AC.

Turn to Us for Professional Furnace Repair

When you need to have your heater repaired without delay, turn to the professionals at Honke Heating & AC. Our pros will fix the issue promptly and have your house feeling cozy again in no time. Call us at 503-663-8033 or contact us online to get an appointment now.