BoilerFaultCodesGlow-worm F72 Fault Code
The Glow-worm F72 fault code means: your boiler has detected that its temperature sensors are giving conflicting readings or have failed, which has caused the system to stop working for safety.. It appears on 9 Glow-worm models in our database.
Technical description: NTC fault
What causes the Glow-worm F72 fault?
This fault occurs when the boiler's control board detects a significant temperature difference between the flow and return pipes that doesn't make sense logically. The most common reason is that one of the internal sensors has either become uncalibrated or has failed completely, leading the boiler to shut down to prevent overheating. In some cases, it can also be caused by a faulty wiring connection between these sensors and the main circuit board.
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 F72 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Glow-worm F72 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