Flashes red/green High

Grant Flashes red/green Fault Code

Also written as FLASHESREDGREEN — same fault.

The Grant Flashes red/green fault code means: your boiler is struggling because the internal water pump is stuck or not receiving power, which prevents heat from circulating through your home.. It appears on 6 Grant models in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: Pump stopped (blocked): Water flowing thorugh pump but no mains voltage to motor
Typical repair cost £150-300 (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 Flashes red/green fault code

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

Source

Grant Flashes red/green 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