Thermostat displays B1 and cannot read humidity; humidity‑based control features are disabled.

Safety first: Turn off power or remove batteries before removing the thermostat from the wall.

• Clean sensor vents: Use a soft brush or compressed air (low pressure) to gently clean any dust from the thermostat vents where the humidity sensor is located.
• Allow drying time: If the thermostat is in a humid area (e.g. bathroom), remove it and allow it to dry in a dry room for several hours.
• Reset device: Perform a factory reset via the menu or by removing power for a few minutes, then reconfigure basic settings.
• Relocate if necessary: If installed in a location with steam or aerosols, consider relocating the thermostat to a more suitable room.
• Replace thermostat: If B1 persists and humidity readings are absent or clearly wrong, the internal sensor is defective and the thermostat should be replaced.