Thermostat displays E12 and the app indicates ‘Battery low’ for the thermostat or wireless sensor.

Safety: Only handle batteries; do not open sealed electronic modules.

• Identify device: In the app, check which Ngenic device reports low battery (thermostat, room sensor, radiator valve).
• Replace with quality cells: Install new, high-quality alkaline or lithium batteries as specified by Ngenic. Observe polarity.
• Check for corrosion: Inspect battery contacts for corrosion; clean gently with a dry cloth if needed.
• Optimize placement: If batteries drain quickly, move the device closer to the control module to reduce RF retransmissions.

Persistent E12 after fresh batteries may indicate a hardware fault in the affected Ngenic device, requiring replacement.