What does the Vaillant S.23 fault code mean?

Your boiler is currently preparing the burner to provide hot water, which is a normal part of its operation.

How much does it cost to fix Vaillant error code S.23?

Cost varies. Contact a Gas Safe registered engineer for a quote.

Vaillant S.23 Fault Code: What It Means & How to Fix It

What the manual says

Manufacturer manual

Hotwaterhandlingmode:Burnerignition

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.

What causes this fault?

This code appears when the boiler detects a demand for hot water and is physically firing up the burner to meet that request. It is a normal part of the start-up sequence and indicates that the internal components are working correctly to heat your water. You will typically see this briefly on the display every time you turn on a hot tap or shower.

DIY fix possible

This fault may be fixable without an engineer. Check your manual first.

Find a Gas Safe engineer

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Related fault codes

S.20View →S.21View →S.24View →

All 170 fault codes on the ecoTEC Plus 625

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

con d.00 D.000 d.01 d.02 d.04 d.05 d.06 d.07 d.08 d.09 d.10 d.11 d.13 d.14 d.15 d.16 d.17 d.18 d.19 d.20 d.21 d.22 d.23 d.24 d.25 d.27 d.28 d.31 d.33 d.34 d.35 d.36 d.39 d.40 d.41 d.43 d.45 d.47 d.50 d.51 d.58 d.60 d.61 d.62 d.64 d.65 d.66 d.67 d.68 d.69 d.70 F.00 F.0 F.01 F.1 F.10 F.11 F.12 F.13 F.20 F.22 F.23 F.24 F.25 F.27 F.28 F.29 F.32 F.33 F.49 F.61 F.62 F.63 F.64 F.65 F.67 F.68 F.70 F.71 F.72 F.73 F.74 F.75 F.76 F.77 F.78 F.83 F.84 F.85 F.86 F.87 F.88 F.89 F.91 F.92 F.97 F22 F70 P.00 P.0 P.01 P.1 P.02 P.2 P.3 P.4 P.5 P.06 P.6 P.07 S.0 S.01 S.1 S.02 S.2 S.03 S.3 S.04 S.4 S.05 S.5 S.06 S.6 S.07 S.7 S.08 S.8 S.10 S.11 S.13 S.14 S.15 S.16 S.17 S.20 S.21 S.22 S.24 S.25 S.26 S.27 S.28 S.30 S.31 S.32 S.33 S.34 S.36 S.39 S.41 S.42 S.46 S.53 S.54 S.88 S.91 S.96 S.97 S.98 S.99 S.108 S.109 T.02 T.03 T.04 T.05 T.06 T.08

Your boiler is currently preparing the burner to provide hot water, which is a normal part of its operation.

What the manual says

What causes this fault?

DIY fix possible

Avoid the next call-out bill

Related fault codes

All 170 fault codes on the ecoTEC Plus 625

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