Furnace troubleshooting

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

While your Lennox® heater can’t speak to you, it has a method to communicate a furnace error.

Its control board has two LED lights that can display a fault code. Depending on the malfunction, your furnace might show steady or flashing lights.

Though there are some elementary HVAC fixes you can do without an expert, many services are best left to experts. When your heater refuses to turn on or give heated air, reach out to Giordanos Heating and Air Conditioning at 203-734-7648 for experienced furnace repair in Derby.

Our specialists will swiftly determine and handle the failure, even if you don’t have a Lennox furnace. We can repair whichever kinds or makes—and get the comfort reintroduced to your house fast.


What Does the Blinking Light on My Furnace Mean?

Your heating system relies on lights to flash code when it requires repairs. It also engages these lights to let you know it’s operating like it should.

Normal operation includes:

  • Concurrent slow flash—heating system working properly.
  • Both lights flash fast—heater is beginning to call for heat.

If you realize that one light flashing slowly and the other blinking quickly, your heater might have a low flame signal. This can occur even when your furnace is running properly. It signifies the flame sensing rod could need to be cleaned or in the wrong spot on the burner. Reach out to us at 203-734-7648 for assistance.

Here are some of the most common faults for Lennox HVAC systems.

Heater Won’t Start

Here are many of the light sequences you might observe when your heat will not or stay on. The majority of these problems need to be handled by an expert, such as one from Giordanos Heating and Air Conditioning.

  1. Both LED lights are extinguished. This indicates your heater might not be receiving power. Check the breaker box to ensure the furnace fuse has not flipped. You should reset the fuse if it has moved into the “off” spot. If it immediately flips after you reset it, don’t touch the breaker and get in touch with us us at 203-734-7648.
  2. An individual light is stable and the other is flashing slowly. This signifies the flame rollout switch is may be open. The component is a critical safety device that assists in stopping fires and carbon monoxide. You shouldn’t attempt to fix this issue yourself.
  3. A single light is blinking rapidly and the other is blinking slowly. This typically means power polarity has been inverted. Your furnace may have a wiring issue that calls for specialized help from Giordanos Heating and Air Conditioning.
  4. Both lights are blinking slowly. This indicates your furnace’s blower motor likely isn’t running. This part circulates hot air from the HVAC system into your house. We can help in figuring out what’s wrong with this component.
  5. A single light is blinking slowly and the other is flickering quickly. This means your HVAC system could have not enough voltage or a short circuit. Call our professionals at 203-734-7648 for help.
  6. One light is flickering on, on and off while the other blinks on, off, on. This signifies there may be a problem with your heater’s control panel or wiring. Giordanos Heating and Air Conditioning can pinpoint the issue and take care of it.
  7. The pair of lights display alternate slow flickers. This signifies your heating system likely has a flame failure. There may be an issue with its gas supply, gas valve or ignitor control. Reach out to us at 203-734-7648 for support.
  8. One light flickers slowly while the other remains steady. This typically indicates your heating system’s limit switch is malfunctioning. The switch prevents your HVAC equipment from becoming too warm. Reach out to the specialists at Giordanos Heating and Air Conditioning for assistance.

Furnace Blower Runs But No Warmth

Here’s what could be broken when you hear your heater’s blower fan on, but you aren’t getting any heated air.

  • The pair of lights are giving every other rapid flashes. This means your furnace ignitor may not be in working order. This part lights gas in your heater to make heat and should be fixed by a specialist from Giordanos Heating and Air Conditioning.

Trust Us for Skilled Furnace Repair

When you need to have your HVAC equipment in working order quickly, trust the professionals at Giordanos Heating and Air Conditioning. Our techs will fix the issue quickly and have your rooms feeling cozy again in a short time. Call us at 203-734-7648 or contact us online to request an appointment today.

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