F.578 Medium

Viessmann F.578 Fault Code

Also written as F578 — same fault.

The Viessmann F.578 fault code means: your boiler has lost the connection to the temperature sensor for your second heating zone, meaning it can no longer accurately read the heat levels in that part of your home.. It appears on 2 Viessmann models in our database.

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description: Lead break, room temperature sensor, heating circuit 2
Typical repair cost £120-220 (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 F.578 fault code

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

Source

Viessmann F.578 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 7 July 2026