Low
d / U on Pro ProCombi Exclusive 24

Your boiler is undergoing a routine self-test of its internal valve to ensure it doesn't get stuck and is not actually a fault code.

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.

What the manual says

Manufacturer manual

The display will alternate between “d” and “U” and the actuator will move into the mid-position.

From this model's manual
Verified against the Pro Procombi Exclusive 24 installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

DIY fix possible

Wait approximately 30 seconds for the sequence to completeMonitor the display until it returns to a standard temperature readingNo action is required as this is part of the boiler's normal maintenance cycle

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