Medium
F35 on Ferroli HiTech RRT 28C

Your boiler is detecting an issue with the electrical power supply frequency coming into your home.

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

Wrong supply frequency

From this model's manual
Verified against the Ferroli/Ferroli Bluehelix Hitech Rrt installation & service 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

F34View →F36View →

All 36 fault codes on the HiTech RRT 28C

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

A06A08A09A11A14A23-A24-F51A26A44A80A88A98A99F05F09F10F11F12F13F15 - A07F19F21F34F37F39F40F47F50F50 - F53F51F53F62F64F96F99Fh

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