BoilerFaultCodesFerroli F11 Fault Code
The Ferroli F11 fault code means: your boiler's internal sensor that monitors the temperature of the water returning to the unit has stopped communicating correctly, causing the system to shutdown for safety.. It appears on 13 Ferroli models in our database.
Technical description: Return sensor error – t-sensor damaged, short circuited, sensor damaged or wiring broken
What causes the Ferroli F11 fault?
This fault occurs when the boiler's internal computer loses the ability to read the temperature of the water coming back from your radiators. This is usually caused by the return sensor failing internally due to age or heat stress, or a loose connection in the wiring that prevents the signal from reaching the main control board.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Ferroli models that show the F11 fault code
Click a model for the full fault code list and model-specific repair notes.
- Arean Repair: £120-220
- Arena 30A Repair: £120-200
- BlueHelix Pro 25C Repair: £100-£180
- BlueHelix Pro 32C Repair: £100-£180
- Bluehelix Tech Repair: £100-£180
- Domi Compact Repair: £120-180
- Domiproject Repair: £90-160
- Econcept 100 Repair: £120-220
- iBoiler 24 Repair: £90-160
- iBoiler 28 Repair: £90-160
- Modena HE Repair: £90-160
- Optima 201 Repair: £120-220
- Optimax Repair: £90-160
Source
Ferroli F11 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