BoilerFaultCodesBiasi Er 99 Fault Code
Also written as ER99 — same fault.
The Biasi Er 99 fault code means: your boiler’s internal computer has forgotten which model it is, meaning it has lost its configuration settings and cannot operate.. It appears on 3 Biasi models in our database.
Technical description: Boiler type not set (parameter P 01 value 00)
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Biasi models that show the Er 99 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Biasi Er 99 fault code information on this page is sourced and cross-checked against the official Biasi service / installation manuals for each affected model.
- Biasi Advance 25C manual (PDF)
- Biasi Advance Plus 16S 25S 30S manual (PDF)
- Biasi Inovia 2020 manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026