High
50 on Atag Q 25CR

Your boiler is having trouble detecting the temperature of the water coming from your taps, which means it cannot heat your hot water properly.

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

T3 (DHW) sensor error (e.g. open, short circuit, out of range)

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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