Furnace troubleshooting

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

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

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

Though there are some basic HVAC fixes you can finish on your own, most repairs are best handled by the professionals. When your furnace won’t kick on or provide heated air, reach out to Woody's Sudden Service Inc at 703-278-2036 for experienced furnace repair in Manassas Park.

Our experts will rapidly spot and handle the fault, even if you don’t own a Lennox heater. We can fix whichever brands or configuration—and get the warmth reintroduced to your home quickly.


What Does the Flashing Light on My Furnace Mean?

Your heating system depends on lights to flash code when it isn’t working right. It also engages this setup to tell you it’s operating properly.

Correct function includes:

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

If you see a lone light flashing slowly and the other blinking fast, your furnace might 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 incorrect spot on the burner. Contact us at 703-278-2036 for assistance.

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

Heater Won’t Kick On

Here are some of the light sequences you may observe when your heating system refuses to or stay on. The majority of these issues need to be taken care of by an expert, like one from Woody's Sudden Service Inc.

  1. The duo of LED lights aren’t lit. This signifies your heating system might not have electricity. Check the breaker box to confirm the furnace fuse is not tripped. You should reset the fuse if it is in the “off” position. If it promptly trips after a subsequent reset, don’t try to reset it again and get in touch with us us at 703-278-2036.
  2. An individual light is stable and the other is flashing slowly. This implies the flame rollout switch is likely malfunctioning. The switch is a critical safety mechanism that aids in preventing fires and carbon monoxide. You shouldn’t try to repair this problem without professional help.
  3. A single light is flickering quickly and the other is flickering slowly. This usually signifies power polarity has been reversed. Your heater could have a wiring error that calls for specialized help from Woody's Sudden Service Inc.
  4. The duo of lights are flashing slowly. This signifies your heating system’s blower motor probably isn’t running. This part moves warm air from the heating system into your residence. We can aid in determining what’s causing a problem with this component.
  5. One light is flickering slowly and the other is blinking rapidly. This means your heater could have insufficient voltage or a short circuit. Contact our technicians at 703-278-2036 for support.
  6. One light is flickering on, on and off while the other flickers on, off, on. This signifies there might be a malfunction with your furnace’s control panel or wiring. Woody's Sudden Service Inc can find the issue and repair it.
  7. The duo of lights are using alternate slow flickers. This means your heater may have a flame problem. There might be trouble with its gas supply, gas valve or ignitor control. Get in touch with us at 703-278-2036 for help.
  8. One light blinks slowly while the other remains solid. This typically signifies your heater’s limit switch is malfunctioning. The switch keeps your heating system from becoming too warm. Call the professionals at Woody's Sudden Service Inc for help.

Heating System Blower Works But No Warm Air

Here’s what could be at fault when you notice your furnace’s blower fan running, but you aren’t receiving any heated air.

  • Both lights display every other fast flickers. This signifies your furnace ignitor may not be working. This part lights energy in your furnace to create warm air and should be fixed by a specialist from Woody's Sudden Service Inc.

Turn to 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 cozy again in no time. Reach out to us at 703-278-2036 or contact us online to get an appointment now.

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