High
11 on Glow-worm Compact 100 System

Your boiler's internal computer is experiencing a communication error, meaning it has safely shut itself down to prevent unpredictable operation.

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.

What the manual says

Manufacturer manual

Control board (inc 16,17)

Shared across the range
This code is shared by the boilers in this range, which use the same control board. It may not be printed in this exact variant’s manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

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

16View →17View →

All 16 fault codes on the Compact 100 System

Seeing a different code? Every code this model can display, in one place.

101213141516171819202122F1F2Pilot will not light

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