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

December 06, 2019

While your Lennox® furnace can’t chat with you, it possesses a process to communicate a furnace error.

Its motherboard has twin LED lights that can show a fault code. Depending on the fault, your heating system might display steady or flashing lights.

Although there are some simple furnace adjustments you can do yourself, most repairs are best left to the professionals. When your furnace will not start or provide heated air, call Kapaun & Brown Inc. at 641-812-2028 for skilled furnace repair in Marshalltown.

Our technicians will swiftly diagnose and handle the malfunction, even if you don’t use a Lennox furnace. We can repair all types or makes—and get the warmth restored to your house quickly.


What Does the Flashing Light on My Furnace Mean?

Your furnace relies on lights to flash code when it is malfunctioning. It also works these lights to tell you it’s operating like it should.

Correct heating consists of:

  • Simultaneous slow flash—heating system working correctly.
  • Simultaneous fast flash—heater is starting to call for heat.

If you notice a lone light blinking slowly and the other blinking quickly, your heater may be experiencing a low flame signal. This can happen even when your heating system is operating like it should. It indicates the flame sensing rod might need to be cleaned or in the wrong location on the burner. Call us at 641-812-2028 for help.

Here are several other of the most common issues for Lennox furnaces.

Furnace Won’t Turn On

Here are a few of the light arrangements you might see when your heater refuses to or keep running. The bulk of these problems must be repaired by a technician, such as one from Kapaun & Brown Inc..

  1. All LED lights aren’t lit. This signifies your HVAC system might not have power. Go to the breaker box to make sure the heater fuse is not triggered. You should reset the fuse if it’s in the “off” position. If it instantly flips following a reset, leave the breaker alone and contact us at 641-812-2028.
  2. A single light is stable and the other is flashing slowly. This means the flame rollout switch is likely malfunctioning. The part is an essential safety device that helps in preventing fires and carbon monoxide. You shouldn’t seek to repair this problem yourself.
  3. An individual light is flashing quickly and the other is blinking slowly. This usually signifies power polarity has been inverted. Your heater might have a wiring problem that needs expert help from Kapaun & Brown Inc..
  4. All lights are blinking slowly. This signifies your furnace’s blower motor likely isn’t working. This part sends hot air from the heating system into your rooms. We can help in determining what’s causing a problem with this piece.
  5. A single light is flickering slowly and the other is flickering rapidly. This signifies your heating system could have insufficient voltage or a short circuit. Reach out to our specialists at 641-812-2028 for assistance.
  6. One light is flickering on, on and off while the other flashes on, off, on. This indicates there might be an error with your heating system’s motherboard or wiring. Kapaun & Brown Inc. can determine the issue and handle it.
  7. The duo of lights display every other slow flickers. This indicates your HVAC system may have a flame failure. There might be an issue with its gas supply, gas valve or ignitor control. Call us at 641-812-2028 for assistance.
  8. A single light flickers slowly while the other is continuous. This often signifies your heater’s limit switch is experiencing an error. The switch stops your furnace from getting too hot. Get in touch with the pros at Kapaun & Brown Inc. for assistance.

Furnace Blower Operates But No Heat

Here’s what might be at fault when you notice your heater’s blower fan on, but you aren’t receiving any heat.

  • The pair of lights display alternate rapid flickers. This signifies your furnace ignitor may not be working. This piece ignites fuel in your heating system to make warmth and should be repaired by a technician from Kapaun & Brown Inc..

Turn to Us for Skilled Furnace Repair

When you need to have your heating system repaired quickly, trust the technicians at Kapaun & Brown Inc.. Our pros will fix the problem quickly and have your space feeling relaxing again in a short time. Get in touch with us at 641-812-2028 or contact us online to request an appointment right away.