How much does it cost to fix Vaillant error code Er.7?

Typical repair cost for the Vaillant Er.7 fault is £180-300 including labour.

Er.7 Medium

Vaillant Er.7 Fault Code

Q: What does the Vaillant Er.7 fault code mean?

Your boiler's internal tank that handles pressure changes is likely losing its charge or leaking, which can lead to system pressure spikes.

Also written as ER7 — same fault.

The Vaillant Er.7 fault code means: your boiler's internal tank that handles pressure changes is likely losing its charge or leaking, which can lead to system pressure spikes.. It appears on 2 Vaillant models in our database.

Technical description: Expansion vessel 10 l

Typical repair cost £180-300 (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.7 fault code

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

Thermocompact Repair: £250-450
Turbomax Pro 28 2E Repair: £180-300

Source

Vaillant Er.7 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