BoilerFaultCodesGrant Flashes red Fault Code
Also written as FLASHESRED — same fault.
The Grant Flashes red fault code means: your boiler has stopped heating because the internal water pump, which moves hot water around your house, has seized up or failed and cannot restart itself.. It appears on 6 Grant models in our database.
Technical description: Pump not operating. Pump stopped (blocked). Pump does not restart itself due to a permanent failure.
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 Flashes red fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Grant Flashes red 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