No Water Flow Fault

A boiler fault code alone is not a gas or carbon-monoxide emergency. If you smell gas, a CO alarm sounds, or someone has possible carbon-monoxide symptoms, leave and call 0800 111 999 from outside.

Safe check: With the boiler off and the system cold, repressurise to 1.0 bar.

Gas Safe registered engineer: If the message remains, contact the installer or arrange a Gas Safe registered engineer.