neon illuminated High

Alpha neon illuminated Fault Code

Also written as NEONILLUMINATED — same fault.

The Alpha neon illuminated fault code means: your boiler's electronic control panel is experiencing an internal fault, causing a warning light to stay on and likely preventing your heating or hot water from working.. It appears on 2 Alpha models in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: 1. Replace neon PCB. 2. check PCB-M11 connector. 3. 20V DC across terminals 49, 52. 4. Replace main PCB.
Typical repair cost £200-350 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Alpha models that show the neon illuminated fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Alpha neon illuminated fault code information on this page is sourced and cross-checked against the official Alpha service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026