High
Slow flash on Grant Vortex Pro 15-26

Your boiler's electronic brain is experiencing a communication error, which is preventing it from firing up reliably.

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.

Technical description

Indicates a possible fault with the PCB (relay). (once every 2 seconds)

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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