Fault Code Guide

Vaillant Boiler Fault Codes

Complete reference for all Vaillant F-codes (faults) and S-codes (status). Find your code, understand the cause, and get it fixed.

Gas safety emergency? If you smell gas or suspect a gas leak, do not use any electrical switches. Call the National Gas Emergency Service on 0800 111 999 immediately and leave the property. Do not call VaillantCare — call the gas emergency line first.

No codes match your search.
Try a different code or keyword, or book an engineer to diagnose your boiler.

Can't find your code or need help now?

Our Gas Safe engineers carry the most common Vaillant parts on their vehicles for first-visit fixes.

Emergency Vaillant Repairs Book a Vaillant Boiler Service