High Lockout
FAIL POINT K on Worcester Bosch 24/28CDi II RSF

Your boiler has encountered a general electrical failure, likely caused by moisture or damage to the internal brain of the unit.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description

Other faults not covered by above - Light indication during fault not covered by above details. Control board is likely to be wet or damaged or malfunctioning.

What causes this fault?

This fault occurs when the boiler's internal computer experiences a critical communication failure or hardware malfunction. The most common reason is moisture ingress from a small leak or heavy condensation getting onto the electrical circuits, though the components can also simply fail over time due to heat stress.

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.

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