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

December 06, 2019

While your Lennox® heater cannot speak to you, it does have a method to tell you about a furnace error.

Its control board has a set of LED lights that can display a fault code. Depending on the fault, your heater may show continuous or flashing lights.

Although there are certain elementary heating adjustments you can complete on your own, the majority of repairs are best left to experts. When your heating system refuses to start or provide heat, reach out to Morgner Inc. Air Conditioning & Heating at 314-262-4541 for skilled furnace repair in St. Louis.

Our specialists will quickly diagnose and repair the breakdown, even if you don’t have a Lennox furnace. We can fix any types or configuration—and get the heat reintroduced to your residence quickly.


What Does the Flickering Light on My Heater Mean?

Your furnace uses lights to flash code when it isn’t working right. It also works this system to tell you it’s operating properly.

Regular operation consists of:

  • Simultaneous slow flash—furnace working properly.
  • Concurrent fast flash—furnace is beginning to call for heat.

If you realize that a single light going on and off slowly and the other flashing rapidly, your heater could be experiencing a low flame signal. This can take place even when your furnace is working like it should. It indicates the flame sensing rod may need to be cleaned or in the bad location on the burner. Contact us at 314-262-4541 for support.

Here are some of the most common issues for Lennox heating systems.

Heating System Won’t Start

Here are a few of the light arrangements you might observe when your furnace won’t turn on or keep operating. The majority of these issues must be repaired by a technician, like one from Morgner Inc. Air Conditioning & Heating.

  1. All LED lights are off. This indicates your heating system might not be receiving power. Find the breaker box to make sure the heater fuse is not flipped. You should reset the fuse if it’s in the “off” position. If it immediately trips following a reset, don’t touch the breaker and call us at 314-262-4541.
  2. One light is unchanging and the other is blinking slowly. This implies the flame rollout switch is probably not working right. The part is an important safety device that helps in preventing fires and carbon monoxide. You shouldn’t try to handle this problem on your own.
  3. A single light is blinking rapidly and the other is flickering slowly. This often indicates power polarity has been reversed. Your furnace might have a wiring issue that requires specialized aid from Morgner Inc. Air Conditioning & Heating.
  4. The duo of lights are flickering slowly. This signifies your heating system’s blower motor likely isn’t running. This part moves heated air from the heater into your rooms. We can aid in pinpointing what’s causing an issue with this piece.
  5. A single light is flashing slowly and the other is flickering rapidly. This signifies your heating system may have low voltage or a short circuit. Get in touch with our experts at 314-262-4541 for assistance.
  6. One light is flashing on, on and off while the other blinks on, off, on. This means there might be a malfunction with your heating system’s control panel or wiring. Morgner Inc. Air Conditioning & Heating can determine the issue and fix it.
  7. The pair of lights show alternating slow blinks. This signifies your HVAC system may have a flame error. There might be trouble with its gas supply, gas valve or ignitor control. Reach out to us at 314-262-4541 for support.
  8. One light blinks slowly while the other remains steady. This often indicates your furnace’s limit switch is malfunctioning. The switch keeps your heater from overheating. Get in touch with the specialists at Morgner Inc. Air Conditioning & Heating for help.

Heating System Blower Works But No Warmth

Here’s what may be broken when you notice your heating equipment’s blower fan running, but you aren’t gaining any warm air.

  • Both lights are showing alternating quick flickers. This signifies your furnace ignitor might not be working. This piece lights gas in your furnace to make warm air and should be fixed by a specialist from Morgner Inc. Air Conditioning & Heating.

Trust Us for Skilled Furnace Repair

When you need to have your HVAC equipment repaired without delay, turn to the specialists at Morgner Inc. Air Conditioning & Heating. Our pros will take care of the issue right away and have your house feeling comfortable again soon. Reach out to us at 314-262-4541 or contact us online to request an appointment now.