Low Warning
72:2 on Viessmann Vitodens 300-W

Your boiler has detected that a hot water sensor is reporting a temperature increase when it was not expected to, likely due to a sensor being in the wrong position or failing.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description

ON during DHW loading to set value 2

What causes this fault?

This fault occurs when the boiler detects an unexpected rise in temperature within the hot water system, suggesting heat is flowing where it shouldn't. The most common reason is a faulty temperature sensor providing incorrect readings or an internal diverter valve that has become stuck, allowing heat to leak into the water cylinder even when the boiler is only supposed to be heating your radiators.

Engineer required

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

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Related fault codes

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