Furnace troubleshooting

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

While your Lennox® heating system isn’t able to chat with you, it does have a way to communicate a furnace error.

Its motherboard has a set of LED lights that can show a fault code. Depending on the fault, your heater might display continuous or flashing lights.

Though there are various basic heating adjustments you can do without an expert, the majority of repairs are best handled by the professionals. When your furnace won’t kick on or give heated air, call Woody's Sudden Service Inc at 703-278-2036 for experienced furnace repair in Manassas Park.

Our experts will rapidly determine and handle the fault, even if you don’t own a Lennox heating system. We can fix all brands or configuration—and get the warmth returned to your home quickly.


What Does the Flashing Light on My Furnace Mean?

Your heater relies on lights to flash code when it isn’t working right. It also engages this setup to tell you it’s running properly.

Correct heating includes:

  • Simultaneous slow flash—heater running correctly.
  • Concurrent fast flash—furnace is initiating the call for heat.

If you see a lone light flashing slowly and the other going on and off fast, your furnace could be having a low flame signal. This can occur even when your heater is working properly. It means the flame sensing rod could be dirty or in the wrong spot on the burner. Reach out to us at 703-278-2036 for help.

Here are several other of the most routine errors for Lennox heaters.

Heater Won’t Kick On

Here are some of the light patterns you may notice when your heating system refuses to or stay on. The majority of these problems must be taken care of by a professional, like one from Woody's Sudden Service Inc.

  1. All LED lights are extinguished. This means your heating system might not be receiving power. Find the breaker box to confirm the furnace fuse is not tripped. You should reset the fuse if it’s in the “off” position. If it immediately trips following a reset, don’t touch the breaker and contact us at 703-278-2036.
  2. An individual light is stable and the other is flashing slowly. This implies the flame rollout switch is probably not working right. The switch is an essential safety mechanism that assists in preventing fires and carbon monoxide. You shouldn’t try to repair this malfunction without professional help.
  3. A single light is flickering quickly and the other is blinking slowly. This typically indicates power polarity has been reversed. Your heater could have a wiring error that needs expert support from Woody's Sudden Service Inc.
  4. The duo of lights are flashing slowly. This indicates your heater’s blower motor probably isn’t operating. This part circulates warm air from the heating system into your residence. We can assist in determining what’s causing an issue with this component.
  5. One light is flickering slowly and the other is blinking rapidly. This means your furnace could have not enough voltage or a short circuit. Contact our technicians at 703-278-2036 for assistance.
  6. One light is flickering on, on and off while the other flickers on, off, on. This indicates there could be a malfunction with your HVAC system’s motherboard or wiring. Woody's Sudden Service Inc can find the fault and take care of it.
  7. The duo of lights display alternate slow blinks. This means your heating system may have a flame problem. There may be an issue with its gas supply, gas valve or ignitor control. Get in touch with us at 703-278-2036 for help.
  8. One light flickers slowly while the other stays solid. This often signifies your heater’s limit switch is malfunctioning. The switch keeps your heater from becoming too warm. Call the experts at Woody's Sudden Service Inc for help.

Heater Blower Operates But No Warm Air

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

  • Both lights display alternate fast blinks. This signifies your furnace ignitor may be broken. This part kindles energy in your heating system to make warmth and should be repaired by a specialist from Woody's Sudden Service Inc.

Depend on Us for Expert Furnace Repair

When you have to get your heater in working order fast, trust the technicians at Woody's Sudden Service Inc. Our techs will repair the fault right away and have your residence feeling relaxing again in no time. Call us at 703-278-2036 or contact us online to schedule an appointment now.

Back To Blog