High Lockout
Fault 01 / 200 on Worcester Bosch Greenstar CDi Compact

Your boiler's internal computer has lost communication with its control components, meaning it cannot receive or send the signals needed to operate.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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

BUS communication fault: Boiler no longer reporting.

What causes this fault?

This fault occurs when the boiler's main brain and its internal components stop talking to each other, often due to an electrical interruption or a fried component. The most common reason is that the main control board has suffered a critical failure, though it can also be caused by loose or damaged wiring inside the unit.

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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Related fault codes

EAView →C6View →FAView →

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