Low
S.22 on Vaillant ecoTEC plus VU GB 656/4-5 A

Your boiler is simply preparing its internal pump to circulate water before it starts heating up your hot water supply.

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

DHWmode:Pumppre-run

From this model's manual
Verified against the Vaillant/Vaillant Ecotec 65kw 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.

What causes this fault?

This fault occurs when the boiler's internal sensors detect that water isn't moving quickly enough through the system to safely transfer heat to your hot water. The most common reason is a blockage caused by limescale or debris in the heat exchanger, or a mechanical failure in the secondary pump that pushes the water around.

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

S.20View →S.21View →S.23View →

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.23S.24S.25S.26S.27S.28S.30S.31S.32S.34S.36S.39S.41S.42S.53S.54S.59S.85S.96S.97S.98S.O

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