BoilerFaultCodesBiasi Er 09 Fault Code
Also written as ER09 — same fault.
The Biasi Er 09 fault code means: your boiler has detected that a sensor measuring the temperature of the exhaust gases is not working correctly, which is preventing the system from running safely.. It appears on 21 Biasi models in our database.
Technical description: Faulty flue temperature probe NTC
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 09 fault code
Click a model for the full fault code list and model-specific repair notes.
- Activ A Repair: £120-220
- Advance 25C Repair: £100-250
- Advance 25S Repair: £100-250
- Advance 25S Repair: £120-220
- Advance 30C Repair: £100-250
- Advance 30C Repair: £120-220
- Advance 30S Repair: £100-250
- Advance 30S Repair: £120-220
- Advance 35C Repair: £100-250
- Advance 35C Repair: £120-220
- Advance Plus Repair: £120-220
- Advance Plus Repair: £120-220
- Advance Plus 16S Repair: £120-220
- Advance Plus 16S 25S 30S Repair: £120-220
- Advance Plus 25C Repair: £100-250
- Advance Plus 30C Repair: £100-250
- Advance Plus 30S Repair: £120-220
- Advance Plus 30S ErP Repair: £100-250
- Advance Plus 30S ErP Repair: £120-220
- Advance Plus 30S ErP Repair: £90-160
- Advance Plus 35C Repair: £100-250
Source
Biasi Er 09 fault code information on this page is sourced and cross-checked against the official Biasi service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 31 August 2026