How much does it cost to fix Grant error code GWB90?

Typical repair cost for the Grant GWB90 fault is £100-200 including labour.

GWB90 Medium

Grant GWB90 Fault Code

Q: What does the Grant GWB90 fault code mean?

This code indicates that the mounting bracket securing your boiler to the wall is either loose, damaged, or incorrectly installed, which could cause the unit to become unstable.

The Grant GWB90 fault code means: this code indicates that the mounting bracket securing your boiler to the wall is either loose, damaged, or incorrectly installed, which could cause the unit to become unstable.. It appears on 1 Grant model in our database.

Technical description: Wall bracket - standard

Typical repair cost £100-200 (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 GWB90 fault code

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

Vortex Repair: £100-200

Source

Grant GWB90 fault code information on this page is sourced and cross-checked against the official Grant service / installation manuals for each affected model.

Grant Vortex manual (PDF)

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