Furnace troubleshooting

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

While your Lennox® heater cannot speak to you, it has a way to communicate a furnace error.

Its motherboard has double LED lights that can display a fault code. Based on the fault, your heater could use solid or flashing lights.

Although there are certain basic furnace fixes you can take care of on your own, the majority of services are best left to experts. When your heater won’t start or give heat, get in touch with Stanford Heating & Cooling at 812-825-8695 for professional furnace repair in Bloomfield.

Our technicians will rapidly detect and fix the issue, even if you don’t have a Lennox heating system. We can fix whichever kinds or models—and get the heat returned to your home without delay.


What Does the Blinking Light on My Heating System Mean?

Your heating system uses lights to flash code when it requires repairs. It also engages this setup to let you know it’s heating properly.

Normal function includes:

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

If you notice one light flashing slowly and the other flashing fast, your heating system might be having a low flame signal. This can occur even when your furnace is working correctly. It means the flame sensing rod may be dirty or in the wrong location on the burner. Reach out to us at 812-825-8695 for assistance.

Here are several other of the most common problems for Lennox heating systems.

Furnace Won’t Turn On

Here are a few of the light arrangements you may see when your heater will not or keep operating. The majority of these issues must be taken care of by a specialist, like one from Stanford Heating & Cooling.

  1. All LED lights aren’t lit. This signifies your furnace might not have power. Check the breaker box to confirm the furnace fuse hasn’t flipped. Attempt to reset the fuse if it is in the “off” spot. If it promptly trips after a subsequent reset, don’t try to reset it again and call us at 812-825-8695.
  2. One light is stable and the other is flickering slowly. This implies the flame rollout switch is probably not working right. The switch is an important safety tool that assists in preventing fires and carbon monoxide. You shouldn’t attempt to handle this malfunction without professional help.
  3. One light is blinking quickly and the other is flickering slowly. This often signifies power polarity has been inverted. Your heating system may have a wiring fault that requires specialized support from Stanford Heating & Cooling.
  4. Both lights are flashing slowly. This means your heater’s blower motor likely isn’t running. This piece sends warm air from the HVAC system into your residence. We can aid in figuring out what’s wrong with this piece.
  5. An individual light is flickering slowly and the other is blinking rapidly. This signifies your heating system could have not enough voltage or a short circuit. Reach out to our professionals at 812-825-8695 for help.
  6. One light is flashing on, on and off while the other blinks on, off, on. This signifies there could be a malfunction with your heater’s control board or wiring. Stanford Heating & Cooling can pinpoint the error and take care of it.
  7. Both lights show alternate slow flickers. This indicates your heating system may have a flame error. There might be an issue with its gas supply, gas valve or ignitor control. Contact us at 812-825-8695 for assistance.
  8. A single light blinks slowly while the other remains continuous. This often means your furnace’s limit switch is open. The switch keeps your HVAC system from overheating. Call the professionals at Stanford Heating & Cooling for support.

Heater Blower Works But No Heat

Here’s what might be at fault when you notice your heater’s blower fan working, but you aren’t getting any heated air.

  • Both lights display alternating fast flashes. This signifies your furnace ignitor might not be in working order. This component lights fuel in your HVAC equipment to create warm air and should be repaired by a professional from Stanford Heating & Cooling.

Turn to Us for Expert Furnace Repair

When you have to get your heater repaired without delay, depend on the specialists at Stanford Heating & Cooling. Our pros will handle the error right away and have your rooms feeling cozy again soon. Reach out to us at 812-825-8695 or contact us online to request an appointment now.

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