High
F0 on Worcester Bosch Greenstar Heatslave II

Your boiler's control system has detected a faulty electrical connection or signs of water leakage inside the main electronic housing, causing it to shut down for safety.

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

Resistors between plug X4 pins 3 & 5 disconnected/>150kΩ or water in the burner control box

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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