Technical Gurus,

Per description, machine with 26K hours, operational in rinse or disinfect modes. Apply dialysis mode and the flow pump turns off then on and no flow to drain, flow error in service screen but not displayed on standard screen. Checked brushes and flow motor was due, so I changed them. At first, did have displayed “Inlet Flow Error”, replaced float switch with new item. Changed out PT 9&10 and calibrated dialysate psi. Changed valve 30 thinking it was sticking. Could it be a bad float switch?
Thank you in advance,

How about a bad bearing in the flow motor? Maybe just sticking enough to stall it out intermittently, or the brushes were worn out and when you rebuilt the motor the magnet moved on the shaft in a little to close and it's sticking. How does the flow motor sound?

Replace actuator board.

Switch the dearation/flow motor harnesses on thedistribution board. If your flow motor runs consistently then it's the actuator board. If it shuts off it's the motor. Hope this helps.

Thanks folks, greatly appreciated. When I checked the brushes on those motors, I failed to check the bearings. Due to time constraints, I kept my note short however I have replaced actuator and functional boards too. I’ll get back on Monday and look things over again, thank you again.

Turned out to be the air separator, the contacts were corroded. Applied some contact cleaner and back in business.