How much does it cost to fix Ferroli error code F12?

Typical repair cost for the Ferroli F12 fault is £90-160 including labour.

F12 Medium

Ferroli F12 Fault Code

Q: What does the Ferroli F12 fault code mean?

Your boiler has lost its connection to the sensor that monitors your hot water temperature, which means you will likely experience cold showers until it is fixed.

The Ferroli F12 fault code means: your boiler has lost its connection to the sensor that monitors your hot water temperature, which means you will likely experience cold showers until it is fixed.. It appears on 9 Ferroli models in our database.

Technical description: Domestic hot water (DHW) sensor fault – sensor damaged, wiring shorted or wiring disconnected – check the wiring

What causes the Ferroli F12 fault?

This fault occurs when the boiler's main control board can no longer communicate with the sensor responsible for measuring your hot water temperature. The most common reason is that the internal sensor has developed a technical failure or the electrical wiring connecting it to the system has come loose or become damaged.

Typical repair cost £90-160 (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 F12 fault code

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

Source

Ferroli F12 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