High
E441 on Navien LCB700

Your boiler is currently unable to sense the temperature of the hot water it is producing, which prevents it from providing you with a reliable supply of hot water.

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

DHW Outlet thermistor Open or Short Circuit

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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