BoilerFaultCodesPotterton Neon4 Fault Code
Also written as NEON4 — same fault.
The Potterton Neon4 fault code means: your boiler has stopped working because it cannot light the flame or the internal drainage pipe is backed up with water.. It appears on 1 Potterton model in our database.
Technical description: Flame Failure or Blocked Condensate Drain
What causes the Potterton Neon4 fault?
This fault occurs when the boiler tries to light but fails to detect a steady flame, or when the internal drain for waste water becomes blocked. The most common reason is a buildup of debris in the condensate trap or a worn-out ignition spark causing a failed startup. If the waste pipe is blocked, the boiler shuts down as a safety precaution to prevent water from backing up into the combustion chamber.
This fault is significantly more common during freezing winter spells, as the external condensate pipe can freeze, causing water to back up and trigger the sensor.
DIY fix possible
Check if your gas prepay meter has credit and that the external gas stopcock is open.Inspect the plastic condensate pipe outside for signs of freezing or blockage; gently pour warm water over it if frozen.Turn the selector switch to the reset position for five seconds, then turn it back to the 'on' position.
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Gas Safe Register →Potterton models that show the Neon4 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Potterton Neon4 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