How much does it cost to fix Grant error code Boiler Fault Finding 12?

Typical repair cost for the Grant Boiler Fault Finding 12 fault is £120-250 including labour.

Boiler Fault Finding 12 Emergency

Grant Boiler Fault Finding 12 Fault Code

Q: What does the Grant Boiler Fault Finding 12 fault code mean?

Your boiler is allowing burnt gases to escape inside or near the unit, which is a serious safety concern that requires an immediate professional inspection.

Also written as BOILERFAULTFINDING12 — same fault.

The Grant Boiler Fault Finding 12 fault code means: your boiler is allowing burnt gases to escape inside or near the unit, which is a serious safety concern that requires an immediate professional inspection.. It appears on 5 Grant models in our database.

Technical description: Combustion fumes smell. Check boiler cleaning cover and seal, burner flange seating, flue seal, and condensate trap.

Typical repair cost £120-250 (including labour)

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 Boiler Fault Finding 12 fault code

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

Source

Grant Boiler Fault Finding 12 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 27 April 2026