Low
9b on Viessmann Vitodens 343-F WS4A

Your boiler's solar hot water add-on has lost contact with one of its temperature sensors, so the solar part of the system can't read its temperature correctly, but your boiler should still heat your home and provide hot water.

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

Control mode. Solar: Lead of the sensor S3 at the Vitosolic broken.

From this model's manual
Verified against the Viessmann/Viessmann Vitodens 343 F Ws4a 5592883 installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

Engineer required

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

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Related fault codes

9AView →9CView →

All 59 fault codes on the Vitodens 343-F WS4A

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

0F9A9C9F10182028303840485058929394A6A7b0b1b4b5b7b8bAbCbdbEbFC2CdCECFdAdbdddEE4E5E8E9EAEbECEdF0F1F2F3F4F8F9FAFCFdFEFF

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