59:0 Low

Viessmann 59:0 Fault Code

Also written as 590 — same fault.

The Viessmann 59:0 fault code means: your boiler is notifying you of a minor adjustment in how it monitors your hot water tank temperature, which shouldn't immediately stop your system from working.. It appears on 5 Viessmann models in our database.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description: DHW cylinder loading: Starting point -2.5K Stopping point +2.5K

What causes the Viessmann 59:0 fault?

This fault occurs when the boiler receives inconsistent or missing data from the probe that monitors your hot water tank. The most common reason is a failing temperature sensor or a loose wire connection, which prevents the boiler from knowing exactly how hot your water is. Without this accurate information, the system cannot safely regulate the heating of your cylinder.

Typical repair cost £90-180 (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 59:0 fault code

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

Source

Viessmann 59:0 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