I have a machine that presented with multiple problems.
1. Dial 1 error - found the diasafe assembly leaking. replaced it. Then I found vavlve 26 bad. replaced that, which fixed the Dial 1 error.
2. When I went to test the machine and the dialysate flow light would not go off. There was no problem in rinse. I tried the actuator cable, actuator board, and lastly the function board. The light still stays on(no flow) in dialysis mode.
Any ideas? Thanks.

The light stays on, but does the button still turn flow on and off?

What is your Conductivity and temperature set at and what is there current readings?

Make sure the all the buttons on the front panel are working. Almost sounds like a bad dialysate flow button, stuck in. Can test buttons in service mode.

condo and temp cannot come up because there isn't any flow. And if you push the button the light starts flashing. All the other buttons are working.

Swap the front touch panel with a known good one and see if the problem is resolved.

Are you getting any alarms such as, "Flow Error", "NO WATER", "Valve Error"?? or is it like you turned off the flow and it just sits there? Is the dearation pump running? I assume the flow pump isn't running, did you pull the flow pump to see if it is froze up or something?

Since your problem started around valve 26 I would look at 24, 25 and 26 real close. When you replaced 26 did you unplugg 24 or 25's coil wires? Is it possible that you have the coil wires on the wrong valve? Thinking it could run in a rinse but not dialysis if this was the case.

Maybe you unplug a valve wire at the valve. check all your connection at all valves.

Thanks for the posts. Turned out to be the sensor board.