F.89
Vaillant fault code
Vaillant F.89: incorrect pump detected
Engineer only
Vaillant describes F.89 on ecoTEC plus boilers as: incorrect pump detected. Possible causes Vaillant lists, for an engineer to check: unsuitable pump connected, PWM plug loose or not plugged in, PCB plug not connected correctly, break in cable harness, electronics defective.
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.