Smart thermostat display is completely blank or frozen and does not respond to touch or buttons.

Safety: Isolate mains power before removing wired thermostats from the wall.

• 1. Check power source: For wired units, verify the boiler or external PSU is powered and supplying the correct voltage. For battery units, replace batteries with new ones.
• 2. Hard reset: Remove the thermostat from its base or remove batteries for 1–2 minutes, then refit to force a reboot.
• 3. Inspect for damage: Look for signs of water ingress, corrosion, or burning on the thermostat housing.
• 4. Test supply at terminals: Use a multimeter to confirm voltage at the thermostat base. If absent, trace back to the boiler or PSU.
• 5. Replace thermostat: If supply is correct but the unit remains blank or frozen, replace the thermostat.