Technical description
SLAVES NON PRESENT There are no slave boards connected
What causes this fault?
This fault occurs when the boiler's main brain loses its connection to the internal sub-boards that coordinate the heating demand. The most common reason is a loose or damaged communication wire between these components, or a electronic failure within one of the secondary control boards themselves.
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.
Find a Gas Safe engineer
Search the official register →