E18
Lux Bluetooth Module Fault

Thermostat displays E18 and cannot detect or pair with Bluetooth setup device (on models using BLE for initial setup)

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Possible Causes

Disabled Bluetooth in installer settings, Internal BLE module failure, RF interference near thermostat

How to Fix / Troubleshooting

Safety: No electrical work is required.

  • Move closer: Stand within a few feet of the thermostat with your phone during pairing.
  • Reduce interference: Temporarily turn off nearby Bluetooth devices that may interfere.
  • Check settings: On the thermostat, ensure Bluetooth or "Local Setup" is enabled in the installer menu.
  • Reboot devices: Restart both the thermostat (via power cycle) and your phone, then retry pairing.
  • Replace thermostat: If E18 persists and Bluetooth remains undiscoverable, the internal BLE module is likely defective and the thermostat should be replaced.
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Repair Difficulty

Easy 2/5

Required Part

Lux Smart Thermostat Bluetooth Module
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