Medium Warning
50 on Atag iC Economiser 25

Your boiler has detected a problem with the sensor that manages your hot water temperature, which may result in your taps running cold or having inconsistent heat.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description

Domestic hot water (DHW) sensor error

What causes this fault?

This fault occurs when the internal sensor responsible for monitoring your hot water temperature has failed or is sending an incorrect signal to the main control board. The most common reason is that the sensor has suffered electrical wear over time or the wiring connecting it to the boiler's computer has come loose or corroded.

Engineer required

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

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