How much does it cost to fix Grant error code GREEN, RED blinking?

Typical repair cost for the Grant GREEN, RED blinking fault is £120-250 including labour.

GREEN, RED blinking High

Grant GREEN, RED blinking Fault Code

Q: What does the Grant GREEN, RED blinking fault code mean?

Your boiler has detected an internal light source that shouldn't be there, so it has safely shut itself down to prevent ignition.

Also written as GREENREDBLINKING — same fault.

The Grant GREEN, RED blinking fault code means: your boiler has detected an internal light source that shouldn't be there, so it has safely shut itself down to prevent ignition.. It appears on 5 Grant models in our database.

Technical description: The burner does not start when there is heat demand. The UV sensor sees an extraneous light. Eliminate the extraneous light.

Typical repair cost £120-250 (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 GREEN, RED blinking fault code

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

Source

Grant GREEN, RED blinking 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