Furnace troubleshooting

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

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

Its control panel has two LED lights that can share a fault code. Based on the issue, your furnace may show continuous or flashing lights.

Though there are some simple heating adjustments you can take care of yourself, most tasks are best taken care of by HVAC technicians. When your furnace refuses to turn on or put out heated air, reach out to M & S Heating & Air LLC at 301-363-4699 for expert furnace repair in Mechanicsville.

Our technicians will quickly determine and handle the issue, even if you don’t have a Lennox heater. We can repair any types or models—and get the warmth restored to your home quickly.


What Does the Flickering Light on My Heater Mean?

Your heating system uses lights to flash code when it requires repairs. It also works this setup to tell you it’s heating like it should.

Correct operation consists of:

  • Both lights flash slowly—heater operating correctly.
  • Concurrent fast flash—heater is beginning to call for heat.

If you see a lone light flashing slowly and the other blinking fast, your heater could be having a low flame signal. This can occur even when your heating system is operating like it should. It indicates the flame sensing rod could need to be cleaned or in the incorrect location on the burner. Call us at 301-363-4699 for help.

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

Heater Won’t Kick On

Here are a few of the light sequences you might notice when your heating system will not or keep running. The majority of these issues must be fixed by an expert, like one from M & S Heating & Air LLC.

  1. Both LED lights are extinguished. This means your furnace might not have electricity. Find the breaker box to confirm the heater fuse hasn’t flipped. Try resetting the fuse if it has moved into the “off” spot. If it immediately trips after you reset it, don’t try to reset it again and contact us at 301-363-4699.
  2. One light is unchanging and the other is flickering slowly. This shows the flame rollout switch is may be malfunctioning. The component is an important safety mechanism that assists in stopping fires and carbon monoxide. You shouldn’t seek to fix this problem yourself.
  3. A single light is flashing fast and the other is flashing slowly. This usually indicates power polarity has been transposed. Your heater might have a wiring problem that needs expert assistance from M & S Heating & Air LLC.
  4. The pair of lights are flickering slowly. This indicates your heater’s blower motor probably isn’t working. This piece distributes heated air from the heater into your space. We can aid in pinpointing what’s wrong with this component.
  5. One light is flashing slowly and the other is blinking fast. This means your heater could have insufficient voltage or a short circuit. Reach out to our experts at 301-363-4699 for support.
  6. One light is flashing on, on and off while the other flashes on, off, on. This signifies there may be trouble with your furnace’s control board or wiring. M & S Heating & Air LLC can locate the error and handle it.
  7. The pair of lights display every other slow blinks. This indicates your furnace possibly has a flame failure. There could be trouble with its gas supply, gas valve or ignitor control. Call us at 301-363-4699 for support.
  8. An individual light blinks slowly while the other remains continuous. This typically indicates your furnace’s limit switch is malfunctioning. The switch stops your heater from overheating. Get in touch with the pros at M & S Heating & Air LLC for assistance.

Heater Blower Works But No Warmth

Here’s what could be wrong when you observe your furnace’s blower fan working, but you aren’t getting any warm air.

  • The duo of lights display every other quick blinks. This signifies your furnace ignitor might not be working. This part kindles fuel in your furnace to create heat and should be fixed by a professional from M & S Heating & Air LLC.

Depend on Us for Skilled Furnace Repair

When you need to get your furnace repaired without delay, depend on the specialists at M & S Heating & Air LLC. Our pros will fix the problem without delay and have your house feeling cozy again in a short time. Call us at 301-363-4699 or contact us online to get an appointment right away.

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