How much does it cost to fix Viessmann error code 65:0?

Typical repair cost for the Viessmann 65:0 fault is £180-350 including labour.

65:0 High

Viessmann 65:0 Fault Code

Q: What does the Viessmann 65:0 fault code mean?

Your boiler has lost communication with the internal valve that directs heated water to either your radiators or your hot water tank, meaning your system cannot function correctly.

Also written as 650 — same fault.

The Viessmann 65:0 fault code means: your boiler has lost communication with the internal valve that directs heated water to either your radiators or your hot water tank, meaning your system cannot function correctly.. It appears on 5 Viessmann models in our database.

Technical description: Without diverter valve

What causes the Viessmann 65:0 fault?

This fault occurs when the boiler's main computer loses its electronic connection with the motor that moves the internal water valve. The most common reason is that the motor unit has failed internally, though it can also be caused by loose wiring or a communication error on the main circuit board.

Typical repair cost £180-350 (including labour)

Engineer required

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

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Viessmann models that show the 65:0 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Viessmann 65:0 fault code information on this page is sourced and cross-checked against the official Viessmann service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026