E440
Lennox
Blower Motor Speed / Configuration Error
Thermostat displays E440; furnace may not run blower or may run at incorrect speeds.
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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
Incorrect blower speed tap configuration (PSC motors), Misprogrammed Lennox variable-speed profile, Faulty blower control relay on board, Loose blower speed wiring
How to Fix / Troubleshooting
Safety: Turn off power before working on blower wiring.
- 1. Identify motor type: Determine if your Lennox furnace uses a PSC (multi-speed) or ECM (variable-speed) blower.
- 2. Check speed taps (PSC): Verify that the correct speed wires are connected to HEAT and COOL terminals per the Lennox wiring diagram on the furnace door.
- 3. Verify programming (ECM): For communicating systems, check blower profiles in the thermostat installer menu. Ensure airflow settings match the furnace size and duct system.
- 4. Inspect relays and connectors: Look for loose or burned blower relay contacts on the control board.
Improper blower configuration can damage equipment; have a technician confirm settings if unsure.
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Repair Difficulty
Hard
4/5
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