F.85
Vaillant fault code
Vaillant F.85: flow and return temperature sensors incorrectly installed
Engineer only
Vaillant describes F.85 on ecoTEC plus boilers as: flow and return temperature sensors incorrectly installed. Possible causes Vaillant lists, for an engineer to check: the flow and/or return sensors have been installed on the same pipe or the wrong pipe.
What you can safely do
There is nothing you can safely do yourself with this one. Leave the boiler off and book an engineer.
Call a Gas Safe engineer if
- Book a Gas Safe registered engineer.
Find a Gas Safe engineer near you
Opens the official Gas Safe Register search.
Applies to: ecoTEC plus. Codes can differ between models, so check your manual.