Have a Fresenius 2008K w/ internal diasfe filter, has about 20,000 hrs, failing diasfe test, replaced filter and transducer. Positive pres test revealed a few small leaks, still fails. Runs fine in dialysis mode and passes all tests. Did notice a flow error when put into diasfe test, not sure if thats normal.

check you deair and flow pressures and valves

Checked pressures, all were OK, whats next

24 psi on the loading pressure....

Check to see if your distribution board cover has pinched the wire going to the valve on the diasafe.

It has the manual valve, not the solenoid

I have seen that tie wrapping the tubing on top of both condo cells and top of air seperator will stop these failures.

Calibrated the dialysate pressure and it passed 3x. You shouldn't have to put wire ties on anything that didn't come that way, no offense but just cut the tubing back or replace