High Lockout
F15 on Glow-worm 30ci Plus

Your boiler has developed a problem with a motor that controls the gas flow, meaning it cannot ignite safely to provide heat or hot water.

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

Stepper motor fault

What causes this fault?

This fault occurs when the small internal motor that regulates the flow of gas into the burner fails to move into the correct position. The most common reason is that the motor's internal components have worn out or become stuck, preventing the boiler from safely controlling the flame. In some cases, the control board may also be failing to send the correct electrical signals to this motor.

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

F1View →F2View →F4View →F17View →

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