What does the Vaillant S.34 fault code mean?

Your boiler has temporarily switched on its internal frost protection mode to prevent the water inside the pipes from freezing.

How much does it cost to fix Vaillant error code S.34?

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

Vaillant S.34 Fault Code: What It Means & How to Fix It

What the manual says

Manufacturer manual

Antifrost mode active

From this model's manual

Verified against the Vaillant/Vaillant Ecotec Plus Pro 839592 00 2004 installation & service manual.

DIY fix possible

Wait a short while for the frost protection cycle to finish and return the boiler to normal operation.Ensure your heating controls are set correctly so your system runs regularly during cold weather.Check that external condensate pipes are properly insulated if temperatures outside drop below freezing.

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Related fault codes

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All 119 fault codes on the ecoTEC plus 612 VU GB 126/3-5

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

d.00 d.01 d.02 d.03 d.05 d.06 d.07 d.08 d.09 d.10 d.11 d.17 d.18 d.19 d.22 d.23 d.25 d.26 d.30 d.33 d.34 d.35 d.36 d.40 d.41 d.44 d.47 d.50 d.51 d.60 d.61 d.64 d.65 d.67 d.68 d.69 d.70 d.71 d.72 d.73 d.75 d.76 d.77 d.78 d.80 d.81 d.82 d.83 d.84 d.90 d.91 d.93 d.97 F.00 F.01 F.02 F.10 F.11 F.13 F.20 F.22 F.23 F.24 F.27 F.28 F.29 F.32 F.60 F.61 F.62 F.63 F.64 F.65 F.70 F.71 F.72 F.73 F.74 F.75 F.76 P.1 P.2 P.3 P.4 P.5 P.6 S.00 S.01 S.02 S.03 S.04 S.05 S.06 S.07 S.08 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.36 S.53 S.54 S.76

Your boiler has temporarily switched on its internal frost protection mode to prevent the water inside the pipes from freezing.

What the manual says

DIY fix possible

Avoid the next call-out bill

Related fault codes

All 119 fault codes on the ecoTEC plus 612 VU GB 126/3-5

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