Moin, have the SuFu tried but not found the right one! My magnetic coupling does not attract… so tested and looked at… plugs and cables all look good, pulley, gap measurement etc. also… only is absolutely zero pressure in the system… either never filled up, I could absolutely imagine with the previous owner… or somewhere a leak! So, before I search now I would like to know first of all if the magnetic coupling works… think that does not attract because sensor reports no pressure in the system! How, where, when can I easily test whether the thing works… must go through bridge or create 12 V somehow!?