How much does it cost to fix Ferroli error code E23?

Typical repair cost for the Ferroli E23 fault is £120-220 including labour.

E23 High

Ferroli E23 Fault Code

Q: What does the Ferroli E23 fault code mean?

The boiler is detecting that its temperature sensors are reporting information in a way that contradicts the system's logic, likely due to a wiring issue or a faulty component.

The Ferroli E23 fault code means: the boiler is detecting that its temperature sensors are reporting information in a way that contradicts the system's logic, likely due to a wiring issue or a faulty component.. It appears on 1 Ferroli model in our database.

Technical description: Flow and return sensors exchange

Typical repair cost £120-220 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Ferroli models that show the E23 fault code

Click a model for the full fault code list and model-specific repair notes.

Maxima 35 S Repair: £120-220

Source

Ferroli E23 fault code information on this page is sourced and cross-checked against the official Ferroli service / installation manuals for each affected model.

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