Stuff that was hard for me to find on the web
Pair / Sync Karcher (Kärcher) K5 Full Control Pressure Washer trigger gun with the machine.
If your Karcher K5 waterblaster trigger gun isn't synched with the main unit, then the display won't work and you won't be able to change pressure or use the detergent dispenser.
I found the following instructions in a comment on https://www.youtube.com/watch?v=41KwJPW4btY
- Set up the pressure washer and turn on
- Once machine is pressurised, hold both the + and – buttons down on the gun
- flashing symbol will appear at the top of the display and the screen should show 3 separate symbols
- Your machine and gun should now be ready to use
In the unlikely event this does not work:
- Turn the machine off at the mains
- Hold the + and – buttons down again until the screen flashes
- Plug the machine back in
- Your machine and gun should now be ready to use
I also found "Pairing Full Control Plus" on https://www.kaercher.com/uk/home-garden/how-to-guides/pressure-washers/pairing-full-control-plus.html