Glow-worm Compact 100 System Fault codes & diagnostics

1 fault code with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.

System Natural Gas
GC Number 41-047-26
Download the Glow-worm Compact 100 System manualThe official installation and service manual (PDF). PDF

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Fault codes

All 1 documented codes

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Pilot will not light

Your boiler is failing to ignite because it cannot start the small flame needed to fire up the main burner.

High Engineer only £120-250 Shared across the range

Parts commonly replaced

  • Pilot injector
  • Piezo igniter
  • Ignition lead
  • Thermocouple
Full explanation for Pilot will not light
Status & diagnostic codes

15 operating states & engineer diagnostics

Not faults — these are normal operating states. Tap to expand.

10 Diagnostic Your boiler is struggling to accurately read the water pressure in your heating system, which may prevent it from starting up reliably. 11 Diagnostic Your boiler's internal computer is experiencing a communication error, meaning it has safely shut itself down to prevent unpredictable operation. 12 Diagnostic Your boiler has developed an internal electrical fault that is preventing it from starting up or operating correctly. 13 Diagnostic Your boiler is failing to detect the gas flow required to ignite the flame, so it has shut itself down as a safety precaution. 14 Diagnostic Your boiler is struggling to detect the temperature of your hot water, which likely means you will have no hot water available until it is fixed. 15 Diagnostic Your boiler is struggling to detect the flow of water needed to provide your hot water and heating, so it has shut down to protect itself. 16 Diagnostic Your boiler has stopped working because an internal safety fuse has blown, cutting off the power to the main controls. 17 Diagnostic Your boiler has stopped working because an internal electrical fuse has blown, cutting off the power needed for it to operate. 18 Diagnostic Your boiler is failing to detect the airflow needed for safe operation, so it has shut down to prevent any unsafe combustion. 19 Diagnostic Your boiler has detected an issue with the internal component that helps control the fan, which is preventing the system from firing up safely. 20 Diagnostic Your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely. 21 Diagnostic Your boiler is struggling to accurately measure the temperature of the water being sent to your radiators, so it has turned itself off as a precaution. 22 Diagnostic Your boiler has detected that it is struggling to remove trapped air from the system, which can prevent heat from circulating properly. F1 Diagnostic Your boiler has failed to ignite the flame, meaning it cannot produce any heat or hot water. F2 Diagnostic Your boiler has stopped working because an internal fuse has blown, preventing the system from receiving the electricity it needs to function.
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