D.014 Low

Vaillant D.014 Fault Code

Also written as D014 — same fault.

The Vaillant D.014 fault code means: this is a technical setting that controls how fast your boiler's internal pump circulates water throughout your heating system.. It appears on 3 Vaillant 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: Diagnostics code: Setting the pump output

What causes the Vaillant D.014 fault?

This isn't a mechanical failure, but rather a configuration setting that has been accessed or adjusted within the boiler's menu. It happens when an engineer or user enters the diagnostic mode to change the speed at which the pump moves hot water around your radiators. It is used to balance the system's efficiency and noise levels rather than to report a broken part.

Typical repair cost £60-120 (including labour)

Engineer required

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

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Vaillant models that show the D.014 fault code

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

Source

Vaillant D.014 fault code information on this page is sourced and cross-checked against the official Vaillant service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026