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.

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.

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

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Lockout fault with a reset-needed pattern.

Safety-critical — turn off, read this.

7 signs repair isn't worth it anymore.