dP Low

Biasi dP Fault Code

Also written as DP — same fault.

The Biasi dP fault code means: your boiler is currently in a manual testing mode used by engineers to check emissions, rather than experiencing a genuine breakdown.. It appears on 3 Biasi models 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: Chimney sweep function step (same as cP on these models)

DIY fix possible

Locate the reset button on your boiler's control panel.Press and release the reset button once.Wait a few minutes for the boiler to return to its normal central heating or hot water operating mode.

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Biasi models that show the dP fault code

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

Source

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

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 31 August 2026