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

December 06, 2019

While your Lennox® heater can’t speak to you, it possesses a process to tell you about a furnace error.

Its control panel has a set of LED lights that can display a fault code. Based on the malfunction, your heater might show solid or flashing lights.

Although there are various basic HVAC adjustments you can finish on your own, most tasks are best taken care of by HVAC technicians. When your heating system will not turn on or deliver warm air, contact B & G HVAC at 641-316-3360 for experienced furnace repair in Marshalltown.

Our experts will rapidly determine and fix the malfunction, even if you don’t have a Lennox furnace. We can service any types or makes—and get the comfort restored to your house without delay.


What Does the Flashing Light on My Furnace Mean?

Your heater uses lights to flash code when it isn’t working right. It also uses this setup to let you know it’s running properly.

Correct heating includes:

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

If you notice a single light blinking slowly and the other blinking quickly, your heater may be having a low flame signal. This can happen even when your furnace is running like it should. It indicates the flame sensing rod could need to be cleaned or in the bad location on the burner. Call us at 641-316-3360 for assistance.

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

Heating System Refuses to Start

Here are a few of the light patterns you might see when your heating system will not or keep operating. The bulk of these errors have to be repaired by a specialist, like one from B & G HVAC.

  1. The pair of LED lights are off. This signifies your furnace might not have electricity. Go to the breaker box to make sure the heater fuse isn’t triggered. Attempt to reset the fuse if it’s in the “off” area. If it instantly flips following a reset, leave the breaker alone and call us at 641-316-3360.
  2. A single light is stable and the other is blinking slowly. This shows the flame rollout switch is probably malfunctioning. The component is an essential safety device that aids in preventing fires and carbon monoxide. You shouldn’t seek to handle this malfunction on your own.
  3. A single light is flickering fast and the other is flashing slowly. This typically signifies power polarity has been inverted. Your heating system could have a wiring fault that requires specialized aid from B & G HVAC.
  4. Both lights are flickering slowly. This indicates your heater’s blower motor probably isn’t running. This part sends warm air from the heater into your home. We can aid in determining what’s causing an issue with this component.
  5. A single light is flashing slowly and the other is blinking fast. This indicates your heating system could have insufficient voltage or a short circuit. Reach out to our experts at 641-316-3360 for help.
  6. One light is blinking on, on and off while the other flashes on, off, on. This signifies there could be trouble with your HVAC system’s control panel or wiring. B & G HVAC can determine the fault and repair it.
  7. The pair of lights display every other slow flickers. This indicates your heating system may have a flame failure. There might be an issue with its gas supply, gas valve or ignitor control. Get in touch with us at 641-316-3360 for help.
  8. One light flickers slowly while the other remains steady. This typically signifies your HVAC equipment’s limit switch is experiencing an error. The switch keeps your HVAC equipment from getting too hot. Call the professionals at B & G HVAC for help.

Heater Blower Operates But No Warmth

Here’s what might be broken when you observe your heating system’s blower fan on, but you aren’t getting any warm air.

  • The duo of lights are giving alternate fast blinks. This means your furnace ignitor may not be working. This piece ignites energy in your furnace to make heat and should be serviced by a technician from B & G HVAC.

Depend on Us for Expert Furnace Repair

When you need to have your heating system fixed without delay, turn to the professionals at B & G HVAC. Our technicians will repair the problem quickly and have your space feeling comfortable again soon. Reach out to us at 641-316-3360 or contact us online to schedule an appointment today.