High
BURNER indicator Slow flash on Grant Vortex Eco External Wall Hung

Your boiler's electronic control centre is experiencing an internal fault and is no longer able to safely communicate with the burner to provide heating or hot water.

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

Slow flash (once every 2 seconds): Indicates a possible fault with the PCB (relay). Replace PCB.

From this model's manual
Verified against the Grant Vortex Pro Internal Combi Installation Servicing Instructions DOC88 Rev00 May 2012 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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