Room temperature reading is significantly higher or lower than actual

Safety first: No live wiring work is required for calibration.

Steps:

• Place a reliable thermometer at the same height and location as the thermostat and compare readings after 15–20 minutes.
• Check that the thermostat is not installed above a radiator, in direct sunlight, or near an external door. If it is, consider relocating or using a Heatmiser remote air sensor in a better location.
• Use the installer menu to adjust the temperature offset (calibration) until the displayed temperature matches the reference thermometer.
• If using a remote sensor, verify its resistance and replace if readings are erratic or far from expected values.