BoilerFaultCodesViessmann 53:1 Fault Code
Also written as 531 — same fault.
The Viessmann 53:1 fault code means: your boiler has detected a communication problem with the pump that circulates hot water around your taps, which may cause delays in getting hot water or stop it altogether.. It appears on 5 Viessmann models in our database.
Technical description: Function connection 28 of the internal extension: DHW circulation pump
What causes the Viessmann 53:1 fault?
This fault occurs when the boiler's control board loses its connection with the pump responsible for moving hot water to your taps. It is usually caused by a failure in the internal electronic expansion module or a loose connection in the wiring harness that bridges these components. In some cases, the pump itself may have developed an electrical fault, preventing it from reporting its status back to the main system.
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 53:1 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Viessmann 53:1 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