What does the Vaillant S.08 fault code mean?

Your boiler is taking a short, normal break after finishing a heating cycle to prevent overheating and ensure everything cools down properly.

How much does it cost to fix Vaillant error code S.08?

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

Vaillant S.08 Fault Code: What It Means & How to Fix It

What the manual says

Manufacturer manual

Heatingmode:Temporaryshutdownafterheatingprocedure

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 occurs when the boiler has successfully met the temperature requested by your thermostat and shuts the burner off to prevent the system from getting too hot. It is a built-in safety delay that allows the internal components to cool down and the water to circulate before the boiler is allowed to fire up again. This 'anti-cycling' period is a normal function designed to protect the heat exchanger and improve energy efficiency.

You may notice this status more frequently in spring and autumn when your home requires less intense heat to reach the desired temperature.

DIY fix possible

Wait 5 to 10 minutes for the status code to change automaticallyCheck that your room thermostat is set to the desired temperatureEnsure radiators are turned on to allow heat to dissipate

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Related fault codes

S.07View →

All 170 fault codes on the ecoTEC Plus 620

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.8 S.10 S.11 S.13 S.14 S.15 S.16 S.17 S.20 S.21 S.22 S.23 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 taking a short, normal break after finishing a heating cycle to prevent overheating and ensure everything cools down properly.

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 620

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