Medium
GEB90 on Grant Vortex

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.

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

Wall bracket - extended

From this model's manual
Verified against the Grant Vortex installation & service manual, page 21.
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.

Find a Gas Safe engineer
Search the official register →
Boiler cover options

Avoid the next call-out bill

A cover plan would handle faults like GEB90: no call-out fees, no surprise bills.

Approved partner
Domestic Appliance Guard
Unlimited call-outs, 24/7 helpline, no price-hike promise
Get a quote →

Affiliate links. We may earn a commission at no extra cost to you.

Related fault codes

GEB60View →GEB100View →

Related guides you might find useful

Yellow or orange flame — CO safety

Safety-critical — turn off, read this.

Read →

New boiler cost 2026

Realistic UK prices for a swap.

Read →

Is boiler cover worth it?

Break-even maths on monthly cover.

Read →