High Lockout
62:2 on Viessmann Vitodens 333-F

Your boiler has detected an issue with the internal pump's operation, causing it to run for a short safety cooling period before pausing.

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

Circulation pump with 2 minutes run-on time

What causes this fault?

This fault occurs when the boiler's control system loses communication with the internal pump or detects that it isn't circulating water correctly. The most common reasons are a physical failure of the pump motor or a fault in the electronic signal between the pump and the main control board. When this happens, the boiler shuts down as a safety measure to prevent the internal components from overheating.

This issue is frequently seen at the start of autumn when a pump that has been inactive all summer becomes 'stuck' or seized upon the first demand for heating.

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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