BoilerFaultCodesGlow-worm Pictogram of a spark Fault Code
Also written as PICTOGRAMOFASPARK — same fault.
The Glow-worm Pictogram of a spark fault code means: your boiler is failing to light because it isn't receiving a steady flow of gas.. It appears on 4 Glow-worm models in our database.
Technical description: No gas supply - gas supply to the boiler has not been turned on or purged sufficiently
What causes the Glow-worm Pictogram of a spark fault?
This fault occurs when the boiler attempts to ignite but cannot detect a flame, usually because the gas supply is blocked or has been interrupted. The most common reasons include a closed manual gas cock, air trapped in the pipes after a service, or a gas valve that is physically unable to open. In some cases, the components that generate the spark or detect the heat may have worn out, preventing the boiler from confirming it has safely lit.
This fault is more common during the first cold snap of winter when gas valves that have been idle through the summer become stuck or fail to respond to the sudden demand for heating.
DIY fix possible
Check that your gas meter has credit and the emergency control valve is turned on.Verify if other gas appliances in your home, like a hob, are working correctly.Press the reset button on the boiler control panel to attempt a restart.
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Gas Safe Register →Glow-worm models that show the Pictogram of a spark fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Glow-worm Pictogram of a spark 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