Furnace troubleshooting

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

While your Lennox® heating system isn’t able to talk to you, it does have a process to tell you about a furnace error.

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

While there are a few simple furnace fixes you can finish yourself, the majority of repairs are best taken care of by HVAC technicians. When your heater will not kick on or give heated air, contact B & B Heating & Cooling at 314-325-7552 for expert furnace repair in Florissant.

Our specialists will rapidly determine and repair the failure, even if you don’t own a Lennox heating system. We can repair whichever brands or makes—and get the warmth restored to your home fast.


What Does the Flashing Light on My Heater Mean?

Your heater uses lights to flash code when it isn’t working right. It also works these lights to relay it’s heating like it should.

Normal operation includes:

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

If you see a lone light flashing slowly and the other flashing rapidly, your furnace could have a low flame signal. This can occur even when your furnace is working properly. It means the flame sensing rod may be dirty or in the bad area on the burner. Contact us at 314-325-7552 for assistance.

Here are some of the most common errors for Lennox furnaces.

Heater Will Not Kick On

Here are many of the light patterns you might notice when your furnace refuses to or stay on. The majority of these errors need to be taken care of by a technician, like one from B & B Heating & Cooling.

  1. The pair of LED lights are extinguished. This indicates your heating system might not be receiving power. Look at the breaker box to ensure the furnace fuse is not flipped. You should reset the fuse if it is in the “off” spot. If it promptly trips after you reset it, don’t touch the breaker and call us at 314-325-7552.
  2. A single light is solid and the other is flashing slowly. This signifies the flame rollout switch is likely open. The part is a critical safety mechanism that helps in preventing fires and carbon monoxide. You shouldn’t seek to handle this malfunction yourself.
  3. An individual light is flickering fast and the other is flashing slowly. This usually signifies power polarity has been inverted. Your heating system might have a wiring error that calls for specialized help from B & B Heating & Cooling.
  4. The pair of lights are flickering slowly. This indicates your heating system’s blower motor possibly isn’t working. This component circulates warm air from the HVAC system into your residence. We can help in determining what’s causing an issue with this component.
  5. A single light is flickering slowly and the other is flashing fast. This indicates your HVAC system might have not enough voltage or a short circuit. Contact our specialists at 314-325-7552 for assistance.
  6. One light is flickering on, on and off while the other flickers on, off, on. This means there could be trouble with your HVAC system’s control board or wiring. B & B Heating & Cooling can locate the issue and repair it.
  7. The duo of lights display alternate slow blinks. This signifies your HVAC system possibly has a flame failure. There might be an issue with its gas supply, gas valve or ignitor control. Reach out to us at 314-325-7552 for support.
  8. A single light blinks slowly while the other is solid. This often indicates your furnace’s limit switch is malfunctioning. The switch keeps your furnace from overheating. Get in touch with the professionals at B & B Heating & Cooling for support.

Furnace Blower Runs But No Warm Air

Here’s what could be broken when you hear your heating system’s blower fan on, but you aren’t getting any heat.

  • The duo of lights are giving every other quick blinks. This indicates your furnace ignitor may be broken. This part ignites energy in your heating system to produce warm air and should be repaired by a technician from B & B Heating & Cooling.

Depend on Us for Expert Furnace Repair

When you need to have your HVAC equipment repaired quickly, turn to the technicians at B & B Heating & Cooling. Our pros will take care of the problem quickly and have your home feeling comfortable again soon. Call us at 314-325-7552 or contact us online to request an appointment right away.

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