Low
S.03 on Vaillant ecoTEC Pro 30

Your boiler is currently trying to light the flame to start your heating, but it is taking a few moments longer than usual to ignite.

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.

What the manual says

Manufacturer manual

Heating mode: Ignition

From this model's manual
Verified against the Vaillant Ecotec Pro 30 installation & service manual, page 34.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

DIY fix possible

Observe the boiler to see if it transitions to code S.04 (Heating mode: Burner ignited)Check that your gas supply is active and turned on at the meterMonitor for any lockout fault codes like F.28 if it fails to ignite

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Related fault codes

F.28View →F.29View →

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