High Lockout
C6215 on Worcester Bosch Greenstar Si Combi / i System

Your boiler's fan is spinning faster than it should, which means the system has stopped running to prevent internal damage.

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

Fan problem – fan running too fast

What causes this fault?

This fault occurs when the boiler's internal computer detects that the fan is spinning at an uncontrollably high speed, which prevents the correct mix of air and gas. The most common reason is an electrical communication failure between the fan and the main control board, or a physical defect within the fan motor itself. Because the boiler cannot safely regulate the flame, it shuts down immediately to protect the internal components.

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

C6View →

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