High
328 on Worcester Bosch Greenstar i

Your boiler's computer is having trouble reading the electricity supply coming from your home, which is causing it to lock itself to prevent damage.

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

Internal error (Mains voltage / frequency may be inconsistent)

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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