9E Medium

Viessmann 9E Fault Code

The Viessmann 9E fault code means: your solar heating system is struggling to move fluid correctly, which could be due to a blockage, air in the pipes, or a safety sensor cutting in to prevent overheating.. 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: No flow rate in solar circuit, or flow rate too low, or temperature limiter responded
Typical repair cost £120-450 (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 9E fault code

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

Source

Viessmann 9E 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