High
RED blinking on Grant Vortex Eco External Wall Hung

Your boiler is failing to start because its internal light sensor is detecting stray light, preventing it from safely igniting.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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.

What the manual says

Manufacturer manual

The burner goes into lockout mode before or during the pre-purging. The UV sensor sees extraneous light. Eliminate the extraneous light.

From this model's manual
Verified against the Grant Vortex Eco installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

Engineer required

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

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