I'm having a problem with a 2008K machine in regards to 'high' TMP (technically low because TMP is a negative measurement). It does not go high enough to alarm, but it runs around 360-420 during a normal treatment and while in the technical office during troubleshooting. This is without the UF pump turned on. I have verified all calibrations numerous times. I have tried swapping in a whole card cage including cables to rule out electronics, which resulted in the problem following the hydraulics, so I know it's not any of the boards (except maybe the distribution board). I have tried swapping the entire balancing chamber (including valves)and hydroblock with known good ones. I have tried bypassing the heat exchanger, tried a new pressure transducer, verified the pump calibrations/incoming water pressure/dialysate pressure/venous pressure/flow, dear, and loading pressures/ all numerous times, even recently and all are good. I have replaced the CFS switch and the entire air separator assembly (valve 43 included) with new parts to rule those out. At this point I'm at a complete loss.
As a side note, I have tried using the troubleshooting guide. Unless you have a problem that causes an alarm state (which I don't, just TMP running higher than it normally should) the guide is next to useless.
I've started heading in the direction of a restriction from a valve starting with bypassing valve 25. I'm looking for some ideas here. Help!!! ;-)