Medium
F12 on Ferroli Bluehelix HiTech RRT

Your boiler is unable to provide hot water because the internal sensor responsible for monitoring water temperature has failed or lost its electrical connection.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

What the manual says

Manufacturer manual

DHW sensor fault — sensor damaged or wiring shorted/disconnected

Shared across the HiTech RRT range
This code is shared by the boilers in this range, which use the same control board. It may not be printed in this exact variant’s manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

Engineer required

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

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Related fault codes

F06View →F10View →A06View →

All 40 fault codes on the Bluehelix HiTech RRT

Seeing a different code? Every code this model can display, in one place.

A01A02A06A07A08A09A11A14A23A24A26A44A65A80A88A98A99F05F09F10F11F13F15F19F21F23F34F35F37F39F40F47F50F51F62F64F65F96F99

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