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

December 06, 2019

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

Its motherboard has a set of LED lights that can show a fault code. Based on the problem, your furnace could use continuous or flashing lights.

While there are various basic HVAC adjustments you can take care of yourself, most repairs are best taken care of by experts. When your furnace won’t turn on or provide warmth, contact Stieferman Heating Company Inc at 573-635-3547 for skilled furnace repair in Jefferson City.

Our experts will rapidly discover and repair the breakdown, even if you don’t have a Lennox furnace. We can repair whichever kinds or makes—and get the heat reintroduced to your house quickly.


What Does the Flickering Light on My Furnace Mean?

Your furnace relies on lights to flash code when it is malfunctioning. It also engages this system to relay it’s running correctly.

Regular function involves:

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

If you notice a single light blinking slowly and the other going on and off rapidly, your furnace could be experiencing a low flame signal. This can occur even when your heater is operating correctly. It indicates the flame sensing rod could be dirty or in the incorrect location on the burner. Reach out to us at 573-635-3547 for support.

Here are a few other of the most typical faults for Lennox HVAC systems.

Heater Will Not Start

Here are a few of the light sequences you could see when your heating system will not or stay on. The bulk of these problems must be repaired by an expert, like one from Stieferman Heating Company Inc.

  1. The duo of LED lights aren’t lit. This indicates your furnace might not have power. Go to the breaker box to confirm the furnace fuse isn’t flipped. Attempt to reset the fuse if it is in the “off” spot. If it instantly flips after a subsequent reset, leave the breaker alone and call us at 573-635-3547.
  2. An individual light is unchanging and the other is blinking slowly. This signifies the flame rollout switch is probably not working right. The part is an important safety guard that aids in avoiding fires and carbon monoxide. You shouldn’t try to handle this problem yourself.
  3. An individual light is flashing quickly and the other is flashing slowly. This typically means power polarity has been inverted. Your furnace could have a wiring issue that requires specialized aid from Stieferman Heating Company Inc.
  4. Both lights are blinking slowly. This means your furnace’s blower motor likely isn’t operating. This component moves warm air from the heating system into your space. We can aid in pinpointing what’s causing a problem with this component.
  5. One light is blinking slowly and the other is flashing rapidly. This means your heating system might have low voltage or a short circuit. Call our technicians at 573-635-3547 for assistance.
  6. One light is blinking on, on and off while the other flashes on, off, on. This means there may be trouble with your heating system’s motherboard or wiring. Stieferman Heating Company Inc can locate the error and repair it.
  7. The pair of lights are using alternate slow flickers. This signifies your heating system possibly has a flame error. There could be a problem with its gas supply, gas valve or ignitor control. Call us at 573-635-3547 for support.
  8. An individual light flashes slowly while the other stays solid. This usually means your furnace’s limit switch is open. The switch prevents your furnace from getting too hot. Call the professionals at Stieferman Heating Company Inc for help.

Furnace Blower Runs But No Warm Air

Here’s what might be wrong when you hear your heater’s blower fan working, but you aren’t receiving any warm air.

  • Both lights are showing alternating rapid blinks. This signifies your furnace ignitor might be broken. This piece kindles fuel in your heating system to produce warmth and should be repaired by an expert from Stieferman Heating Company Inc.

Depend on Us for Professional Furnace Repair

When you have to have your HVAC equipment repaired without delay, depend on the experts at Stieferman Heating Company Inc. Our techs will handle the issue promptly and have your space feeling relaxing again in a short time. Call us at 573-635-3547 or contact us online to schedule an appointment right away.