High
9b on Viessmann Vitodens 200-W WB2C 19kW System

The boiler has lost the signal from the sensor that measures the hot water tank's temperature, so it may not be heating your water properly, though your heating should usually still work.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

What the manual says

Manufacturer manual

Control mode. Cause: lead break, cylinder temperature sensor

From this model's manual
Verified against the Viessmann/Viessmann Vitodens 200 W Wb2c Service 5692857 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 is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

9CView →

All 82 fault codes on the Vitodens 200-W WB2C 19kW System

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

4C9A9C9E9F1018202830384044485051585990919293949899A7b0b1b5b7b8bAbbbCbdbEbFC1C2C3C4C5C6C7C8CdCECFd6d7d8dAdbdCdddEdFE0E1E3E4E5E7E8EAEbECEdEEEFF0F1F2F3F8F9FAFCFdFEFF

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