A10 error; no hot water despite demand, or unit cycles rapidly

Safety: Close the cold water inlet and isolate power before removing any water connections.

• 1. Check water demand: Open a hot tap fully. If the heater does not recognize flow and A10 appears, the flow detection is not working.
• 2. Clean inlet filter: Close the cold inlet valve to the Beretta heater. Remove the inlet filter (usually at the cold inlet connection) and rinse out debris and limescale.
• 3. Inspect flow switch/turbine: Depending on model, there may be a mechanical flow switch or a turbine sensor. Remove carefully and check for dirt or scale preventing movement. Clean gently.
• 4. Check wiring: Ensure the flow sensor connector is firmly seated on the PCB and that cables are not damaged.
• 5. Replace faulty sensor: If the sensor is physically damaged or does not change state when water flows (technician test), replace with a genuine Beretta flow sensor.