E14
Lux
Stage 2 Output Fault (W2/Y2)
Thermostat displays E14 and second-stage heat or cool will not engage
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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
Shorted W2 or Y2 conductor, Misconfigured staging in installer setup, Failed stage 2 relay on thermostat
How to Fix / Troubleshooting
Safety: Turn off HVAC power at the breaker.
- Verify system type: In the Lux installer menu, confirm that the system actually has a second stage and that W2/Y2 is configured correctly.
- Inspect W2/Y2 wiring: Remove the thermostat and check the W2/Y2 wire for damage or shorts.
- Isolate stage 2: Disconnect W2/Y2 at the thermostat, restore power, and see if E14 clears. If it does, inspect the wiring and stage 2 relay/zone board at the equipment.
- Check equipment side: At the furnace or air handler, verify the W2/Y2 terminal is not shorted to C and that any staging board is not burned or damaged.
- Replace thermostat: If E14 persists with W2/Y2 disconnected and configuration correct, the internal stage 2 relay is likely defective and the thermostat should be replaced.
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Repair Difficulty
Hard
4/5
Required Part
Lux Smart Thermostat Stage 2 Output Circuit
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