Low
9A on Viessmann Vitodens 333-F

Your boiler has lost communication with the sensor that monitors your solar heating panels, likely due to a damaged or disconnected wire.

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 - Collector temperature sensor lead break

From this model's manual
Verified against the Viessmann/Viessmann Vitodens 333 F 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.

What causes this fault?

This fault occurs when the boiler's control system can no longer detect a signal from the temperature sensor located on your roof's solar panels. The most common reasons are a wire being damaged by wildlife, such as birds or squirrels, or a connection point becoming loose or corroded due to exposure to the elements.

This fault is often identified during the spring and summer months when homeowners notice their solar thermal system isn't contributing to their hot water production as expected.

Engineer required

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

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Related fault codes

All 75 fault codes on the Vitodens 333-F

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

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