How much does it cost to fix Vaillant error code D.61?

Typical repair cost for the Vaillant D.61 fault is £120-450 including labour.

D.61 High

Vaillant D.61 Fault Code

Q: What does the Vaillant D.61 fault code mean?

Your boiler is recording that it has repeatedly failed to light or stay on, leading to multiple safety shutdowns.

Also written as D61 — same fault.

The Vaillant D.61 fault code means: your boiler is recording that it has repeatedly failed to light or stay on, leading to multiple safety shutdowns.. It appears on 28 Vaillant models in our database.

Technical description: Number of unsuccessful lockouts

What causes the Vaillant D.61 fault?

This fault occurs when the boiler tries to ignite multiple times but fails to establish a stable flame, causing the system to lock out for safety. The most common reasons include a lack of gas supply, worn-out ignition parts that can no longer spark, or a build-up of carbon on the electrodes that prevents the boiler from 'sensing' the flame.

This fault is more common during extreme cold spells, as frozen external gas regulators or blockages in the flue can prevent the consistent gas flow and ventilation required for ignition.

Typical repair cost £120-450 (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 D.61 fault code

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

Source

Vaillant D.61 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