COdE Low

Atag COdE Fault Code

Also written as CODE — same fault.

The Atag COdE fault code means: your boiler is asking for a secure service password, which usually appears during routine maintenance or setup and indicates it is currently locked from standard operation.. It appears on 4 Atag models in our database.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description: Prompt to enter the installer access code.
Typical repair cost £80-120 (including labour)

Engineer required

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

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Atag models that show the COdE fault code

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

Source

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

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