Er.2 High

Vaillant Er.2 Fault Code

Also written as ER2 — same fault.

The Vaillant Er.2 fault code means: your boiler is failing to light the burner because it cannot detect a flame or spark, meaning you currently have no heating or hot water.. 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: Ignition electrode / Flame sensing electrode
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 Er.2 fault code

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

Source

Vaillant Er.2 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 7 July 2026