BoilerFaultCodesFerroli A05 Fault Code
The Ferroli A05 fault code means: your boiler has stopped working because its internal fan, which safely exhausts gases, is not communicating correctly with the main control board.. It appears on 10 Ferroli models in our database.
Technical description: Fan error – tachometer signal interrupted for 1 hour or longer
What causes the Ferroli A05 fault?
This fault occurs when the boiler's control board loses track of how fast the fan is spinning, meaning it can no longer safely manage the flow of air and exhaust gases. The most common reason is a mechanical failure within the fan motor or a loose electrical connection that prevents the speed signal from reaching the main computer. In some cases, a fault on the control board itself means it can no longer 'hear' the fan, even if the fan is spinning correctly.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Ferroli models that show the A05 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ferroli A05 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