Thermostat shows E11 and cannot control a specific smart radiator thermostat (TRV)

Safety first: Smart radiator thermostats are battery powered and safe to handle. Do not disturb any hot pipework without protection.

• Check TRV batteries: Replace with new alkaline cells. Ensure correct polarity and that the battery cover is fully closed.
• Wake the TRV: Press its front button to wake it and check for any local error indication (e.g. flashing LED).
• Improve signal: If the TRV is far from the Heat Hub, consider adding another Wiser device (e.g. another thermostat) in between to act as a Zigbee repeater, or relocate the Heat Hub away from metal enclosures.
• Re-pair TRV: In the Wiser app, remove the problematic radiator thermostat, then add it again following the pairing instructions.
• If E11 persists on one TRV only: The TRV’s radio module may be faulty. Replace the smart radiator thermostat.