Technical description
Internal fault Replace control board
What causes this fault?
This fault occurs when the boiler's internal computer experiences a critical electronic failure, preventing it from processing signals or managing components safely. The most common reasons are age-related wear on the circuit board's capacitors or an electrical surge that has damaged the delicate microchips. Because the control board can no longer communicate with the rest of the boiler, the system shuts down immediately as a safety precaution.
This fault is occasionally more frequent during winter months due to increased electrical load on the system and a higher likelihood of power fluctuations during stormy weather.
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.