54:1 Low

Viessmann 54:1 Fault Code

Also written as 541 — same fault.

The Viessmann 54:1 fault code means: your boiler's solar control system is having trouble communicating with its temperature sensors or the pump, meaning your solar water heating may not be working correctly.. 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: With Vitosolic 100

What causes the Viessmann 54:1 fault?

This fault occurs when the main boiler loses its connection with the Vitosolic solar control module, essentially causing a breakdown in communication between the two systems. The most common reason is a loose or damaged data cable, though a malfunction within the solar controller itself can also trigger the alert.

This fault is often more noticeable during the summer months when the household relies more heavily on solar energy rather than gas to heat their water.

Typical repair cost £90-220 (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 54:1 fault code

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

Source

Viessmann 54:1 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