Low
S.06 on Vaillant ecoTEC Plus 635

Your boiler is temporarily running the internal fan to cool the system down after the heating has switched off.

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

Heatingmode:Fanoverrun

Shared across the range
This code is shared by the boilers in this range, which use the same control board. It may not be printed in this exact variant’s manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

What causes this fault?

This occurs because the boiler’s internal heat exchanger is still very hot after a period of intense heating or hot water production. To protect the internal components and prevent heat damage, the boiler keeps the fan spinning for a short time to dissipate that leftover thermal energy. It is a completely normal safety function and does not indicate that anything is broken.

DIY fix possible

No action is required as this is a normal operating status and not a fault.Wait a few minutes for the fan to stop and the code to change.Ensure your radiators are open to allow heat to dissipate naturally.

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Related fault codes

S.07View →S.08View →

All 170 fault codes on the ecoTEC Plus 635

Seeing a different code? Every code this model can display, in one place.

cond.00D.000d.01d.02d.04d.05d.06d.07d.08d.09d.10d.11d.13d.14d.15d.16d.17d.18d.19d.20d.21d.22d.23d.24d.25d.27d.28d.31d.33d.34d.35d.36d.39d.40d.41d.43d.45d.47d.50d.51d.58d.60d.61d.62d.64d.65d.66d.67d.68d.69d.70F.00F.0F.01F.1F.10F.11F.12F.13F.20F.22F.23F.24F.25F.27F.28F.29F.32F.33F.49F.61F.62F.63F.64F.65F.67F.68F.70F.71F.72F.73F.74F.75F.76F.77F.78F.83F.84F.85F.86F.87F.88F.89F.91F.92F.97F22F70P.00P.0P.01P.1P.02P.2P.3P.4P.5P.06P.6P.07S.0S.01S.1S.02S.2S.03S.3S.04S.4S.05S.5S.6S.07S.7S.08S.8S.10S.11S.13S.14S.15S.16S.17S.20S.21S.22S.23S.24S.25S.26S.27S.28S.30S.31S.32S.33S.34S.36S.39S.41S.42S.46S.53S.54S.88S.91S.96S.97S.98S.99S.108S.109T.02T.03T.04T.05T.06T.08

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