BoilerFaultCodesGlow-worm Neon1 Fault Code
Also written as NEON1 — same fault.
The Glow-worm Neon1 fault code means: your boiler has lost power or has insufficient water pressure to operate safely, meaning it cannot provide heating or hot water until reset.. It appears on 12 Glow-worm models in our database.
Technical description: Fault with mains supply, PCB fuse or low water pressure switch.
What causes the Glow-worm Neon1 fault?
This fault occurs when the boiler's internal computer stops receiving a steady flow of electricity or detects that the system doesn't have enough water to function. The most common reason is a simple drop in water pressure, but it can also be triggered by a blown internal fuse or a failing main circuit board. Because the boiler cannot guarantee it will run safely under these conditions, it shuts down entirely as a protective measure.
DIY fix possible
Check the pressure gauge on the front of the boiler or in your airing cupboard; if below 1.0 bar, top it up using the filling loopCheck your home's consumer unit (fuse box) to ensure the heating circuit hasn't trippedSwitch the boiler off at the wall, wait 30 seconds, and switch it back on to reset the electronics
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Gas Safe Register →Glow-worm models that show the Neon1 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Glow-worm Neon1 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