BoilerFaultCodesGlow-worm 36 Fault Code
The Glow-worm 36 fault code means: your boiler has stopped working because a sensor that measures the temperature of the water heading to your radiators is sending an incorrect or broken signal.. It appears on 1 Glow-worm model in our database.
Technical description: The heating flow thermistor is too resistant.
What causes the Glow-worm 36 fault?
This fault occurs when the main control board detects a signal from the heating sensor that is outside of its normal operating range. The most common reason is that the internal components of the sensor have degraded over time, causing it to report an impossible temperature, or there is a loose connection in the wiring leading back to the boiler's computer.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Glow-worm models that show the 36 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Glow-worm 36 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