GEB90 Medium

Grant GEB90 Fault Code

The Grant GEB90 fault code means: your boiler is flagging an issue with the mounting bracket used for an external flue installation, often indicating that the flue pipe is not securely fixed or supported correctly.. It appears on 1 Grant model in our database.

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.

Technical description: Wall bracket - extended
Typical repair cost £120-250 (including labour)

Engineer required

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

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Grant models that show the GEB90 fault code

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

Source

Grant GEB90 fault code information on this page is sourced and cross-checked against the official Grant service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026