High
F.29 on Vaillant Ecomax Condensing 600/800 series

Your boiler has stopped because the flame inside has gone out and will not stay lit, meaning you currently have no heating or hot water.

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

Flame extinguished re–ignition unsuccessful, Gas supply absent or insufficient, Check flue duct

From this model's manual
Verified against the Vaillant Ecomax Condensing 600 800 Series installation & service manual, page 49.
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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F.27View →F.28View →

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