53:2 High

Viessmann 53:2 Fault Code

Also written as 532 — same fault.

The Viessmann 53:2 fault code means: your boiler's internal computer is reporting an electrical fault with the pump that circulates hot water to your radiators, meaning your heating may not turn on correctly.. It appears on 5 Viessmann models in our database.

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: Function relay 2: External heating circuit pump (heating circuit without mixer)

What causes the Viessmann 53:2 fault?

This fault occurs when the boiler's main control board loses the electrical signal required to run the external pump that moves water through your radiators. The most common reasons are a complete mechanical failure of the pump motor, a loose connection in the wiring, or a fault within the internal control board itself.

This issue is most frequently noticed during the first cold spell of autumn when the pump is required to run for the first time after being idle all summer.

Typical repair cost £180-450 (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 53:2 fault code

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

Source

Viessmann 53:2 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