BoilerFaultCodesGlow-worm 30 Fault Code
The Glow-worm 30 fault code means: your boiler detects a flame when it shouldn't, which is causing it to shut down for safety.. It appears on 1 Glow-worm model in our database.
Technical description: There is a flame signal without there being a flame present.
What causes the Glow-worm 30 fault?
This fault occurs when the boiler's internal sensor incorrectly detects a flame after the burner has been told to switch off. This is most commonly caused by a carbon-coated or damaged sensing probe sending a false electrical signal, or a moisture-damaged control board misreading the system's status.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Glow-worm models that show the 30 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Glow-worm 30 fault code information on this page is sourced and cross-checked against the official Glow-worm service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026