E411
Lennox Ignition Failure / Ignitor Fault (communicating report)

Thermostat displays E411; furnace may not ignite or may shut down shortly after starting.

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Cracked hot surface ignitor, Loose ignitor wiring harness, Low line voltage to ignitor, Faulty ignitor relay on Lennox control board

How to Fix / Troubleshooting

Safety: Turn off power and gas before accessing the burner compartment.

  • 1. Visual inspection: Locate the hot surface ignitor near the burners. Inspect for cracks, white spots, or broken elements. Do not touch the element with bare fingers.
  • 2. Check connector: Ensure the ignitor plug is fully seated on the Lennox control board harness and that wires are not frayed.
  • 3. Replace ignitor if damaged: Remove the mounting screw, gently pull out the ignitor, and install a Lennox-approved replacement of the same type and rating. Avoid contact with the element.
  • 4. Restore power and test: Turn power and gas back on, then call for heat and observe ignition.

If the ignitor does not glow with a new part installed, the control board or wiring should be tested by a technician.

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Repair Difficulty

Medium 3/5

Required Part

Hot Surface Ignitor
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