Low
9A on Viessmann Vitodens 200-W B2HB-35

The boiler has lost the signal from a sensor that measures the temperature of the solar panels on the roof, so it can't use free solar energy to help heat your water, but your normal heating and hot water should still work.

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

Lead break, collector temperature sensor

From this model's manual
Verified against the Viessmann/Viessmann Vitodens 200 W B2hb B2kb 5792013 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

9BView →9CView →

All 89 fault codes on the Vitodens 200-W B2HB-35

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

9b9C9E9F10181920283038505158597071737475768080/EE8181/EE8282/EE838485909192939495969899A3A7A9B0b1b5b7B8bFC1C2C3C4C5CdCFd3d4d5d6d7d8E0E1E2E3E4E5E7E8E9EAEbECEdEEEFF0F1F2F3F8F9FAFbFCFdFEFF

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