How much does it cost to fix Grant error code Flashes red/green?

Typical repair cost for the Grant Flashes red/green fault is £150-300 including labour.

Flashes red/green High

Grant Flashes red/green Fault Code

Q: What does the Grant Flashes red/green fault code mean?

Your boiler is struggling because the internal water pump is stuck or not receiving power, which prevents heat from circulating through your home.

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 5 Grant models in our database.

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 27 April 2026