BoilerFaultCodesTechnical description
It is essential that there is no air in the heat exchanger and the system prior to firing the appliance. This will cause nF1 fault and prevent you finishing the installation without hinderance.
What causes this fault?
This fault occurs when air becomes trapped inside the main heat exchanger, preventing the boiler from successfully finishing its startup sequence. It is usually caused by a faulty automatic air vent or air that was not properly purged from the system after a refill or a repair.
This fault is most common in autumn when homeowners turn their heating back on for the first time or after radiators have been bled to prepare for winter.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.