BoilerFaultCodesTechnical description
Control box failure
What causes this fault?
This fault occurs when the boiler's internal computer experiences a critical electronic failure that prevents it from managing the heating process. The most common reason is the gradual degradation of electrical components on the main circuit board, which eventually stops the boiler from being able to safely run its startup sequence.
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 →