Low
1.W4 on Worcester Bosch Greenstar Heatslave II

Your boiler has detected very cold temperatures and has automatically turned on your heating to protect the system from freezing.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description

Weather Compensation Functionality - System frost protection enable.

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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