How much does it cost to fix Biasi error code E15?

Typical repair cost for the Biasi E15 fault is £90-180 including labour.

E15 High

Biasi E15 Fault Code

Q: What does the Biasi E15 fault code mean?

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.

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 5 Biasi models in our database.

Technical description: Return probe temperature higher than flow probe temperature

Typical repair cost £90-180 (including labour)

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.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026