High
d.69 on Vaillant ecoFIT Pure 435

Your boiler is struggling to light its flame and is failing on the second try, which usually indicates an issue with the fuel supply or the ignition components.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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.

What the manual says

Manufacturer manual

Number of unsuccessful ignitions at 2nd attempt

From this model's manual
Verified against the Vaillant Ecofit Pure 830 installation & service manual, page 31.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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