Thermostat display shows E1 and heating will not turn on or off from the thermostat.

Safety first: Turn off power to the heating system and thermostat at the fused spur or consumer unit before removing any covers.

• Power down: Isolate the boiler/heating circuit and the thermostat receiver (e.g. Drayton SCR or RF receiver module).
• Inspect sensor wiring: If using a wired Drayton room sensor or remote sensor, remove the thermostat from its wall plate and check the NTC sensor leads for breaks, cuts, or loose screws at the terminal block.
• Check connectors: On models with plug-in sensor looms, gently unplug and re-seat the sensor connector on the thermostat PCB, ensuring it clicks fully home.
• Measure resistance: With power still off, use a multimeter to measure the NTC sensor resistance at room temperature. Compare to Drayton’s specification (typically around 10kΩ at 25°C). If the reading is infinite (open circuit), the sensor is faulty.
• Replace sensor: If open circuit is confirmed, replace the room NTC sensor or the complete thermostat front module (e.g. Drayton Wiser Room Thermostat front) following the installation guide. Restore power and clear the error by rebooting the thermostat.