24/7 Emergency Support

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

December 06, 2019

While your Lennox® furnace isn’t able to talk to you, it does have a procedure to get your attention when there’s a furnace error.

Its control panel has double LED lights that can display a fault code. Based on the malfunction, your furnace could display continuous or flashing lights.

Although there are various basic furnace repairs you can take care of on your own, many tasks are best left to the professionals. When your furnace won’t turn on or put out warmth, contact PWA Heating & Cooling Inc at 815-410-1231 for skilled furnace repair in Plainfield.

Our experts will quickly diagnose and take care of the malfunction, even if you don’t use a Lennox heater. We can service any brands or models—and get the warmth returned to your residence fast.


What Does the Blinking Light on My Furnace Mean?

Your heating system relies on lights to flash code when it is malfunctioning. It also works these lights to let you know it’s running properly.

Normal function includes:

  • Both lights flash slowly—furnace operating correctly.
  • Both lights flash fast—heating system is beginning to call for heat.

If you see a single light flashing slowly and the other going on and off quickly, your heater may have a low flame signal. This can take place even when your heater is working like it should. It indicates the flame sensing rod might have build-up or in the bad area on the burner. Contact us at 815-410-1231 for assistance.

Here are several other of the most typical issues for Lennox HVAC systems.

Heating System Refuses to Kick On

Here are many of the light sequences you might see when your furnace will not or keep heating. The bulk of these problems need to be repaired by a professional, such as one from PWA Heating & Cooling Inc.

  1. All LED lights are extinguished. This means your heating system might not have power. Check the breaker box to ensure the heating system fuse has not tripped. Attempt to reset the fuse if it is in the “off” area. If it instantly turns off following a reset, don’t touch the breaker and call us at 815-410-1231.
  2. One light is continuous and the other is blinking slowly. This shows the flame rollout switch is likely malfunctioning. The part is an essential safety mechanism that aids in preventing fires and carbon monoxide. You shouldn’t attempt to handle this problem yourself.
  3. An individual light is blinking rapidly and the other is blinking slowly. This typically signifies power polarity has been reversed. Your heater may have a wiring issue that needs specialized aid from PWA Heating & Cooling Inc.
  4. The duo of lights are blinking slowly. This means your heating system’s blower motor likely isn’t operating. This part moves heated air from the heating system into your space. We can help in figuring out what’s causing an issue with this component.
  5. A single light is blinking slowly and the other is blinking rapidly. This indicates your heating system could have low voltage or a short circuit. Contact our technicians at 815-410-1231 for support.
  6. One light is flickering on, on and off while the other flashes on, off, on. This means there might be an issue with your heating system’s control panel or wiring. PWA Heating & Cooling Inc can find the problem and take care of it.
  7. The pair of lights show every other slow flickers. This indicates your heating system likely has a flame error. There may be an issue with its gas supply, gas valve or ignitor control. Call us at 815-410-1231 for help.
  8. An individual light flashes slowly while the other is continuous. This usually indicates your heating system’s limit switch is not working. The switch stops your furnace from overheating. Get in touch with the experts at PWA Heating & Cooling Inc for assistance.

Heater Blower Operates But No Warmth

Here’s what may be wrong when you notice your furnace’s blower fan on, but you aren’t getting any warmth.

  • Both lights are showing alternating fast flashes. This indicates your furnace ignitor may be broken. This piece kindles fuel in your heater to make warm air and should be fixed by a specialist from PWA Heating & Cooling Inc.

Turn to Us for Professional Furnace Repair

When you have to get your heater in working order fast, turn to the experts at PWA Heating & Cooling Inc. Our technicians will take care of the problem without delay and have your space feeling relaxing again in a short time. Call us at 815-410-1231 or contact us online to request an appointment right away.