BoilerFaultCodesBiasi An Fault Code
Also written as AN — same fault.
The Biasi An fault code means: your boiler is failing to light the flame or keep it running, which means it has safely shut itself down to prevent gas from building up.. It appears on 5 Biasi models in our database.
Technical description: Flame detection error
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 →Avoid the next call-out bill
A cover plan would handle faults like An: no call-out fees, no surprise bills.
Affiliate links. We may earn a commission at no extra cost to you.
Biasi models that show the An fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Biasi An fault code information on this page is sourced and cross-checked against the official Biasi service / installation manuals for each affected model.
- Biasi Activ A manual (PDF)
- Biasi Advance Plus 16S 25S 30S manual (PDF)
- Biasi Concept 400 20 1 Mfs manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026