Low Information
S.3 on Vaillant ecoMAX 622

Your boiler is currently trying to start the ignition process to provide heating, which is a normal part of the startup sequence and not necessarily a fault unless it remains stuck on this screen.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description

Ignition sequence (heating operation)

What causes this fault?

This status occurs when the boiler begins the physical process of lighting the burner to heat your radiators. It is a natural part of the start-up cycle where the system checks components and prepares the spark to ignite the gas. If the boiler stays on this code without moving forward, it usually means the system is struggling to successfully establish or detect a flame.

DIY fix possible

Check if the display changes to a different code after a few minutesMonitor for any lockout fault codes like F.28 or F.29Ensure your thermostat is calling for heat

Find a Gas Safe engineer
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Related fault codes

S.1View →S.2View →S.4View →F.28View →F.29View →

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