00:5 Low

Viessmann 00:5 Fault Code

Also written as 005 — same fault.

The Viessmann 00:5 fault code means: your boiler is correctly configured for your specific heating setup and this code is simply informing you how your system is currently set up to operate.. 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: System design 2, 3: 1 heating circuit without mixer A1 and 1 mixer circuit M2, without DHW heating

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 00:5 fault code

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

Source

Viessmann 00:5 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