High
D.93 on Vaillant Atmomax

Your boiler has lost its identity settings, meaning it has forgotten exactly which model it is and cannot operate safely until it is reprogrammed.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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

DSN appliance variant setting

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

F.70View →F.27View →

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