Condensation or visible moisture inside thermostat or Smart Radiator Valve housing.

Safety: Disconnect batteries or power before handling wet electronics.

• Remove power: Take out batteries from the thermostat or valve. If the Relay is affected, unplug it from mains.
• Dry the device: Place the device in a warm, dry room for at least 24–48 hours. Do not use direct heat sources like ovens or hairdryers.
• Relocate: After drying, reinstall the device in a less humid location if possible.
• Inspect for corrosion: If you see rust or green/white deposits inside, the electronics may be permanently damaged.

Devices that have been significantly wet or show corrosion should be replaced; moisture damage is usually not repairable.