Furnace troubleshooting

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

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

Its motherboard has two LED lights that can display a fault code. Depending on the problem, your heater could display steady or flashing lights.

Although there are various basic furnace repairs you can complete without an expert, the majority of repairs are best handled by experts. When your furnace will not kick on or provide warm air, contact Cronin-Verheul Heating & A/C Ltd at 519-664-0600 for skilled furnace repair in Waterloo.

Our specialists will quickly detect and fix the issue, even if you don’t have a Lennox furnace. We can repair whichever kinds or makes—and get the heat restored to your residence quickly.


What Does the Flashing Light on My Furnace Mean?

Your heating system depends on lights to flash code when it is malfunctioning. It also uses these lights to tell you it’s working properly.

Regular function involves:

  • Both lights flash slowly—heater heating properly.
  • Simultaneous fast flash—heater is starting to call for heat.

If you realize that a single light flashing slowly and the other blinking rapidly, your heater may be experiencing a low flame signal. This can occur even when your furnace is working like it should. It indicates the flame sensing rod could have build-up or in the incorrect location on the burner. Contact us at 519-664-0600 for assistance.

Here are a few other of the most typical problems for Lennox furnaces.

Furnace Won’t Start

Here are a few of the light patterns you might notice when your heater won’t turn on or keep heating. The bulk of these errors must be repaired by an expert, like one from Cronin-Verheul Heating & A/C Ltd.

  1. The duo of LED lights are off. This means your heater might not have power. Find the breaker box to make sure the heating system fuse is not tripped. Attempt to reset the fuse if it’s in the “off” area. If it promptly turns off following a reset, don’t try to reset it again and get in touch with us us at 519-664-0600.
  2. One light is stable and the other is flickering slowly. This implies the flame rollout switch is probably open. The component is an important safety device that helps 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 often means power polarity has been inverted. Your furnace might have a wiring issue that needs expert assistance from Cronin-Verheul Heating & A/C Ltd.
  4. The duo of lights are flashing slowly. This indicates your heater’s blower motor likely isn’t working. This piece distributes heated air from the heating system into your home. We can assist in pinpointing what’s causing a problem with this piece.
  5. An individual light is flashing slowly and the other is flashing fast. This signifies your furnace may have low voltage or a short circuit. Contact our specialists at 519-664-0600 for help.
  6. One light is blinking on, on and off while the other blinks on, off, on. This signifies there might be a problem with your heater’s control board or wiring. Cronin-Verheul Heating & A/C Ltd can locate the issue and fix it.
  7. The pair of lights show alternating slow flickers. This means your heater likely has a flame failure. There might be a problem with its gas supply, gas valve or ignitor control. Call us at 519-664-0600 for help.
  8. An individual light flashes slowly while the other stays continuous. This typically means your HVAC system’s limit switch is experiencing an error. The switch stops your heater from becoming too warm. Contact the professionals at Cronin-Verheul Heating & A/C Ltd for assistance.

Heating System Blower Works But No Warmth

Here’s what could be at fault when you observe your heater’s blower fan running, but you aren’t getting any heated air.

  • The duo of lights are giving alternating rapid flashes. This means your furnace ignitor might not be in working order. This piece ignites fuel in your heating system to make warmth and should be serviced by an expert from Cronin-Verheul Heating & A/C Ltd.

Depend on Us for Skilled Furnace Repair

When you need to get your heating system fixed quickly, depend on the specialists at Cronin-Verheul Heating & A/C Ltd. Our technicians will handle the problem quickly and have your residence feeling cozy again in no time. Get in touch with us at 519-664-0600 or contact us online to get an appointment today.

Back To Blog