Potterton neon illuminated Fault Code
Also written as NEONILLUMINATED — same fault.
The Potterton neon illuminated fault code means: your boiler is receiving electrical power and is switched on, but it is currently in standby mode waiting for a signal to provide heat or hot water.. It appears on 4 Potterton models in our database.
Technical description: Boiler has power and selector is in ON position.
What causes the Potterton neon illuminated fault?
This indicator shows that the boiler is functional and waiting for a command to start heating. If your home is cold, the most common reason is that the external thermostat or timer is set too low or has failed to send a 'call for heat' signal to the unit. Essentially, the boiler is ready to work, but it hasn't been told to turn on yet.
This situation is more frequent during the first cold spell of autumn when external thermostats or timers are first adjusted after being off all summer.
DIY fix possible
Check that your room thermostat is turned up higher than the current room temperature.Ensure the heating programmer or timer is set to 'ON' or 'AUTO'.Check that the thermostatic radiator valves (TRVs) are turned open.
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Gas Safe Register →Potterton models that show the neon illuminated fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Potterton neon illuminated fault code information on this page is sourced and cross-checked against the official Potterton service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026