Medium
F7 on Viessmann Vitodens 100-W WB1A

Your boiler has lost the signal from the sensor that monitors your hot water tank, meaning it currently doesn't know when the water has reached the right temperature.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

What the manual says

Manufacturer manual

No DHW heating Lead break, cylinder temperature sensor

From this model's manual
Verified against the Viessmann Vitodens 100 W Wb1a installation & service manual, page 83.
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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