My K was failing Neg Stabilize. Changed dailysate o-rings, adn now fails Neg Flow On.

Ideas?

Change hanson orings on the red and blue dialysate lines. Run negative and positive pressure tests, you have a leak somewhere.

Diasafe filter change, deaeration, loading and/or floating pressures, could be the issue.

The majority of my negative pressure test failures have come from cracks in blue hanson, right below the opening for fluid input. In fact, if you look closely with a flashlight, I think that you will find several machines with at least a start of a crack right below this opening. It finally gets to a point where it leaks more than the allowable (21 mmHg), a good way to isolate is to open the hansen door right when negative pressure test begins, causing bypass. That way, you can see if it is external leakage (blue hanson to red hansen) or internal (leakage in hydraulics). I check each hansen connector every PM now to avoid this problem. Preventive Maintenance procedures added to checklist can sometimes make our lives easier.

Proper calibration of TMP - dialysate pressure should help. Good luck.

SOunds odd, but I was told a long time ago by my FSR that the screws on the air separator work loose. DOn't need much torque, just a little. It fixed my leaks some times.