How much does it cost to fix Vaillant error code Er.16?

Typical repair cost for the Vaillant Er.16 fault is £200-450 including labour.

Er.16 High

Vaillant Er.16 Fault Code

Q: What does the Vaillant Er.16 fault code mean?

Your boiler is struggling to exchange heat effectively to provide hot water, which may cause your hot tap water to run cold or the system to stop working entirely.

Also written as ER16 — same fault.

The Vaillant Er.16 fault code means: your boiler is struggling to exchange heat effectively to provide hot water, which may cause your hot tap water to run cold or the system to stop working entirely.. It appears on 2 Vaillant models in our database.

Technical description: DHW heat exchanger*

Typical repair cost £200-450 (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 Er.16 fault code

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

Source

Vaillant Er.16 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