BoilerFaultCodesViessmann 62:0 Fault Code
Also written as 620 — same fault.
The Viessmann 62:0 fault code means: your boiler's internal pump is failing to stay on long enough to safely dissipate heat after the burner turns off, which can cause the system to overheat.. It appears on 5 Viessmann models in our database.
Technical description: Circulation pump without run-on
What causes the Viessmann 62:0 fault?
This fault occurs when the boiler's control system detects that the internal pump has stopped spinning immediately after the heat cycle ends, rather than continuing to circulate water to cool the heat exchanger down. The most common reason is a failing pump motor that has developed a dead spot or mechanical resistance, preventing it from performing its crucial post-run cooling phase. In some cases, a communication error from the main circuit board means the pump isn't receiving the command to keep running.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Viessmann models that show the 62:0 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Viessmann 62:0 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