Medium
S.59 on Vaillant ecoTEC plus VU GB 656/4-5 A

Your boiler is pausing because it cannot detect enough water flowing through the system to operate safely.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

What the manual says

Manufacturer manual

Waitingperiod:Minimumvolumeofcirculationwaternotachieved

From this model's manual
Verified against the Vaillant/Vaillant Ecotec 65kw installation & service manual, page 35.
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

Check that all radiator valves throughout your home are fully open.Check your system pressure gauge and top up to 1.5 bar if low.Ensure any external system pump or zone valves are powered on and functioning.

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Related fault codes

F.22View →S.51View →S.52View →

All 122 fault codes on the ecoTEC plus VU GB 656/4-5 A

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

D.0D.1D.2D.4D.5D.7D.8D.9D.10D.11D.12D.13D.14D.15D.17D.18D.20D.22D.23D.25D.26D.27D.28D.30D.33D.34D.40D.41D.44D.47D.50D.51D.60D.61D.64D.65D.67D.68D.69D.71D.72D.75D.76D.77D.78D.80D.81D.82D.83D.84D.90D.91D.93D.96D.97D.98F.0F.1F.10F.11F.13F.20F.22F.23F.24F.27F.28F.29F.32F.49F.61F.62F.63F.64F.65F.67F.70F.71F.72F.73F.74F.75F.77P.0P.1P.2P.5P.6S.0S.1S.2S.3S.4S.5S.6S.7S.8S.20S.21S.22S.23S.24S.25S.26S.27S.28S.30S.31S.32S.34S.36S.39S.41S.42S.53S.54S.85S.96S.97S.98S.O

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