d Low

Pro d Fault Code

Also written as D — same fault.

The Pro d fault code means: your boiler is currently working correctly and is simply letting you know that it is providing hot water to your taps.. It appears on 1 Pro model in our database.

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: DHW being supplied.
Typical repair cost £0 (including labour)

DIY fix possible

No action is required; this is a normal status message.The code will disappear once you turn off the hot water tap.

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Pro models that show the d fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Pro d fault code information on this page is sourced and cross-checked against the official Pro service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026