Room never reaches the set temperature; the thermostat shows demand, but the room stays cold.

Safety first: Isolate the mains before working on any valves or wiring.

• Check radiators/TRVs: Ensure radiators in the thermostat room are fully open and TRVs are not stuck. Carefully free any stuck TRV pins.
• Verify control mode: In the Drayton thermostat or Wiser app, confirm that the control type (radiator vs. underfloor) and cycle rate are set correctly for your system.
• Compare temperatures: Use a separate thermometer to compare with the thermostat reading. If the thermostat reads significantly higher, the sensor may be faulty or poorly located.
• Relocate or replace sensor: Move the thermostat to a more representative location or replace the thermostat if the sensor is inaccurate.