High
E44 on Keston Celsius 25

Your boiler has lost signal from the pipe that monitors water returning from your radiators, meaning it cannot safely regulate the heating temperature.

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

Return sensor open circuit – check connections to return sensor are in place

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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Related fault codes

E43View →E05View →

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