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

December 06, 2019

While your Lennox® heater cannot speak to you, it has a method to tell you about a furnace error.

Its control panel has a set of LED lights that can show a fault code. Based on the fault, your heater could show continuous or flashing lights.

Though there are a few elementary HVAC adjustments you can complete without an expert, most fixes are best taken care of by experts. When your furnace will not kick on or put out warm air, call Street Heating and Cooling at 605-206-3915 for professional furnace repair in Rapid City.

Our technicians will quickly spot and take care of the breakdown, even if you don’t own a Lennox heating system. We can fix all types or models—and get the warmth returned to your home fast.


What Does the Flickering Light on My Heater Mean?

Your heater uses lights to flash code when it requires repairs. It also engages these lights to relay it’s working like it should.

Correct function includes:

  • Simultaneous slow flash—furnace operating like it should.
  • Both lights flash fast—heater is starting to call for heat.

If you see a single light blinking slowly and the other going on and off rapidly, your furnace could be experiencing a low flame signal. This can occur even when your furnace is running correctly. It means the flame sensing rod may have build-up or in the wrong area on the burner. Contact us at 605-206-3915 for assistance.

Here are some of the most typical errors for Lennox HVAC systems.

Heater Will Not Turn On

Here are some of the light arrangements you could notice when your heater won’t turn on or keep running. Most of these issues must be repaired by a technician, for instance from Street Heating and Cooling.

  1. The duo of LED lights are extinguished. This indicates your HVAC system might not be receiving power. Check the breaker box to confirm the heater fuse hasn’t triggered. Attempt to reset the fuse if it is in the “off” position. If it immediately trips following a reset, don’t try to reset it again and call us at 605-206-3915.
  2. A single light is continuous and the other is blinking slowly. This implies the flame rollout switch is likely malfunctioning. The part is an essential safety guard that assists in avoiding fires and carbon monoxide. You shouldn’t try to handle this problem yourself.
  3. One light is flickering fast and the other is blinking slowly. This usually means power polarity has been inverted. Your heating system could have a wiring issue that needs specialized support from Street Heating and Cooling.
  4. All lights are flickering slowly. This means your furnace’s blower motor probably isn’t running. This part moves warm air from the HVAC system into your home. We can aid in figuring out what’s wrong with this part.
  5. A single light is flickering slowly and the other is flashing rapidly. This signifies your heater might have not enough voltage or a short circuit. Contact our technicians at 605-206-3915 for support.
  6. One light is flickering on, on and off while the other flickers on, off, on. This signifies there might be an issue with your heater’s control board or wiring. Street Heating and Cooling can determine the problem and handle it.
  7. The pair of lights display alternate slow flickers. This indicates your heating system may have a flame error. There may be a problem with its gas supply, gas valve or ignitor control. Call us at 605-206-3915 for help.
  8. One light flickers slowly while the other remains continuous. This typically signifies your furnace’s limit switch is experiencing an error. The switch prevents your heater from becoming too warm. Contact the experts at Street Heating and Cooling for assistance.

Heating System Blower Works But No Warm Air

Here’s what may be broken when you notice your heater’s blower fan running, but you aren’t gaining any heated air.

  • The pair of lights are giving every other fast flickers. This indicates your furnace ignitor could be broken. This component kindles gas in your furnace to create heat and should be fixed by a professional from Street Heating and Cooling.

Turn to Us for Expert Furnace Repair

When you have to get your furnace in working order without delay, trust the technicians at Street Heating and Cooling. Our techs will take care of the fault without delay and have your rooms feeling comfortable again in no time. Get in touch with us at 605-206-3915 or contact us online to schedule an appointment now.