Furnace troubleshooting

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

While your Lennox® heating system cannot speak to you, it does have a process to get your attention when there’s a furnace error.

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

Though there are various basic heating repairs you can finish on your own, many repairs are best taken care of by HVAC technicians. When your heater won’t kick on or give heat, reach out to Contra Costa Heating & AC at 510-343-9841 for skilled furnace repair in the Bay Area.

Our specialists will quickly diagnose and handle the malfunction, even if you don’t have a Lennox heater. We can fix all brands or models—and get the heat returned to your residence fast.


What Does the Blinking Light on My Furnace Mean?

Your heating system uses lights to flash code when it is malfunctioning. It also uses these lights to tell you it’s operating properly.

Normal heating consists of:

  • Concurrent slow flash—furnace heating correctly.
  • Both lights flash fast—furnace is beginning to call for heat.

If you see a lone light flashing slowly and the other going on and off fast, your heater might have a low flame signal. This can happen even when your furnace is running like it should. It indicates the flame sensing rod may need to be cleaned or in the wrong area on the burner. Call us at 510-343-9841 for assistance.

Here are a few other of the most typical errors for Lennox furnaces.

Heating System Won’t Turn On

Here are many of the light patterns you may notice when your heater won’t turn on or keep operating. The majority of these problems need to be fixed by a professional, such as one from Contra Costa Heating & AC.

  1. All LED lights are off. This means your heating system might not have power. Examine the breaker box to confirm the heating system fuse has not flipped. You should reset the fuse if it’s in the “off” area. If it instantly trips following a reset, leave the breaker alone and call us at 510-343-9841.
  2. A single light is unchanging and the other is flickering slowly. This means the flame rollout switch is may be malfunctioning. The component is an important safety guard that aids in preventing fires and carbon monoxide. You shouldn’t seek to repair this malfunction without professional help.
  3. One light is blinking quickly and the other is flashing slowly. This likely means power polarity has been transposed. Your heating system may have a wiring problem that calls for professional assistance from Contra Costa Heating & AC.
  4. The duo of lights are blinking slowly. This signifies your furnace’s blower motor possibly isn’t working. This part distributes hot air from the heating system into your house. We can help in figuring out what’s causing a problem with this piece.
  5. One light is flickering slowly and the other is blinking rapidly. This means your heating system might have insufficient voltage or a short circuit. Reach out to our professionals at 510-343-9841 for help.
  6. One light is blinking on, on and off while the other blinks on, off, on. This indicates there may be an issue with your furnace’s motherboard or wiring. Contra Costa Heating & AC can determine the fault and repair it.
  7. The duo of lights are using alternating slow flashes. This indicates your HVAC system may have a flame problem. There might be trouble with its gas supply, gas valve or ignitor control. Get in touch with us at 510-343-9841 for assistance.
  8. An individual light flashes slowly while the other is continuous. This usually indicates your HVAC system’s limit switch is experiencing an error. The switch prevents your HVAC system from overheating. Get in touch with the pros at Contra Costa Heating & AC for assistance.

Furnace Blower Operates But No Heat

Here’s what could be broken when you observe your heater’s blower fan on, but you aren’t receiving any warm air.

  • Both lights display alternating quick flickers. This signifies your furnace ignitor may be broken. This component ignites gas in your heater to produce heat and should be repaired by a professional from Contra Costa Heating & AC.

Trust Us for Professional Furnace Repair

When you have to get your heating system repaired fast, trust the technicians at Contra Costa Heating & AC. Our techs will take care of the problem quickly and have your residence feeling comfortable again soon. Call us at 510-343-9841 or contact us online to request an appointment now.

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