A63 / A64 / F66 High

Ferroli A63 / A64 / F66 Fault Code

Also written as A63A64F66 — same fault.

The Ferroli A63 / A64 / F66 fault code means: your boiler's internal computer has developed a technical fault and can no longer communicate with the rest of the system, causing it to shut down for safety.. It appears on 3 Ferroli models in our database.

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: Controller ABM03B error – controller internal error
Typical repair cost £250-£450 (including labour)

Engineer required

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

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Ferroli models that show the A63 / A64 / F66 fault code

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

Source

Ferroli A63 / A64 / F66 fault code information on this page is sourced and cross-checked against the official Ferroli service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026