High
Loss of water indicating light on Saunier Duval Sylva

Your boiler has stopped working because the water pressure inside the heating system has dropped too low.

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 that the system pressure has dropped or there is a loss of water in the system (pressure gauge less than 1 bar).

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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