High Lockout
65:0 on Viessmann Vitodens 200-W

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.

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.

Technical description

Without diverter valve

What causes this 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.

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

65:1View →65:2View →F4View →

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