Viessmann boilers Low

Viessmann Viessmann boilers Fault Code

Also written as VIESSMANNBOILERS — same fault.

The Viessmann Viessmann boilers fault code means: your boiler is currently operating based on internal settings rather than external controls, meaning it may be ignoring your thermostat or running according to the temperature set on the boiler panel itself.. 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: Control mode
Typical repair cost £0-120 (including labour)

DIY fix possible

Check that your room thermostat is turned up and has working batteriesEnsure the heating and hot water dials on the boiler front panel are set to your desired temperatureCheck if any external timers or smart controls are disconnected or powered off

Find a Gas Safe engineer

Search the official register for a qualified engineer in your area.

Gas Safe Register →

Viessmann models that show the Viessmann boilers fault code

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

Source

Viessmann Viessmann boilers 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