A1.2 Low

Grant A1.2 Fault Code

Also written as A12 — same fault.

The Grant A1.2 fault code means: your boiler is simply indicating that the burner is currently firing up and running as it should, so there is no fault to worry about.. It appears on 6 Grant 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: Burner operating status indicator

Engineer required

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

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Grant models that show the A1.2 fault code

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

Source

Grant A1.2 fault code information on this page is sourced and cross-checked against the official Grant service / installation manuals for each affected model.

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