12 Low

Malvern 12 Fault Code

The Malvern 12 fault code means: your boiler is displaying a power output reading rather than a fault, which usually indicates the system is in its start-up configuration mode.. It appears on 1 Malvern model 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: kW (40944 Btu/h)

Engineer required

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

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Malvern models that show the 12 fault code

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

Source

Malvern 12 fault code information on this page is sourced and cross-checked against the official Malvern service / installation manuals for each affected model.

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