High Lockout
S.06 on Glow-worm Flexicom hx

Your boiler is staying in a cooling-down phase for too long because the fan is still running after it should have stopped.

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 overrun

What causes this fault?

This fault occurs when the boiler's control system detects that the fan is still spinning even after the heating cycle has finished and the cooling period should have ended. The most common reason is a communication error between the main circuit board and the fan, or a mechanical stickiness within the fan motor itself that prevents it from stopping correctly.

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 →

Related fault codes

S.32View →

Related guides you might find useful

Boiler keeps losing pressure

Six most common causes of dropping pressure.

Read →

Banging / kettling / whistling noise

Each noise points to a different fault.

Read →

Boiler keeps cutting out

Lockout fault with a reset-needed pattern.

Read →