P3 High

Vaillant P3 Fault Code

The Vaillant P3 fault code means: your boiler is struggling to accurately detect its current temperature, which has caused it to pause its heating operation as a safety precaution.. It appears on 1 Vaillant model in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: Mid setting point
Typical repair cost £120-250 (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 P3 fault code

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

Source

Vaillant P3 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