Thermostat shows E2 and reports incorrect room temperature (very high or very low) while heating behaves erratically.

Safety first: Isolate mains power to the heating system and thermostat receiver before inspection.

• Remove thermostat: Take the Drayton thermostat off its wall plate or open the housing to access the sensor wiring.
• Check for moisture: Look for condensation or water ingress around the sensor area, especially if mounted on an external wall. Dry the area thoroughly and improve sealing if needed.
• Inspect cable: Follow the sensor cable route and look for crushed or pinched sections behind the backplate or in trunking that could cause a short.
• Test resistance: With a multimeter, measure the NTC sensor resistance. A near-zero reading indicates a short. Compare to Drayton’s specified curve.
• Replace faulty parts: Replace the NTC sensor or the thermostat front module if the sensor is integrated. Reassemble, restore power, and confirm that the displayed temperature is realistic and the E2 code has cleared.