BoilerFaultCodesGlow-worm 06 Fault Code
The Glow-worm 06 fault code means: your boiler has detected a problem with the sensor that measures the temperature of the water going to your radiators, causing the system to stop working for safety.. It appears on 8 Glow-worm models in our database.
Technical description: Central heating flow NTC fault
What causes the Glow-worm 06 fault?
This fault occurs when the internal sensor responsible for monitoring the heat of the water leaving the boiler fails or sends an incorrect signal. The most common reason is that the sensor has physically degraded over time or developed an electrical short, meaning the boiler can no longer safely regulate its temperature. In some cases, it may be caused by loose or damaged wiring connecting the sensor to the main control board.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Glow-worm models that show the 06 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Glow-worm 06 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 7 July 2026