Your boiler has lost its digital connection to your room thermostat, meaning it no longer knows when to turn the heating on or off.

DIY fix possible

Check if the batteries in your Alpha Climatic controller are dead and replace them if necessary.Ensure the control unit is firmly mounted on its backplate to maintain a solid electrical connection.Turn the boiler off at the fused spur for 60 seconds and switch it back on to force a reconnection.