BoilerFaultCodesBiasi E15 Fault Code
The Biasi E15 fault code means: your boiler has sensed that the water returning from your radiators is hotter than the water leaving the boiler, which usually indicates an internal sensor error or a problem with water circulation.. It appears on 4 Biasi models in our database.
Technical description: Return probe temperature higher than flow probe temperature
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 E15 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Biasi E15 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 Antares Combi manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026