Today I had a Fresenius K that passed test and then showed a Dial Valve Failure that wouldn't reset. Have never seen or even heard of this alarm. Anyone?

Act Bd, Valve 24, 25, 26 or limit switch bad / stuck in hanson door.

I have seen this a couple of times and each time it was the limit switch in the shunt door like old F guy mentioned.

what is limit switch

We have seen this intermittently on the ne K machines we installed this year. The following is the response I got from a fresenius trainer:

Refer to K-Block Diagram C for the following discussion:

This failure is due to the function board 'sensing' that valve #24 is still powered (solenoid receiving 24 volts from the actuator board) when it is supposed to be powered off (solenoid receiving 0 volts). Valve #24 should be powered off whenever a bypass alarm occurs (conductivity or temperature alarm violation). The function board data bit, called DIALVLO, can be seen in debug screen 2 and is directly from valve #24's actuator board driver. DIALVLO should be = 0 (0 volts) when a bypass alarm occurs, = 1 (24 volts) with no bypass alarm. If it remains = 1 when a bypass alarm occurs the machine issues the "DIAL VALVE FAIL 1" message and shuts down the 24 volt supplies to the hydraulic and blood systems to protect the patient. This is a 'so called' fatal alarm and requires a machine power down to reset it.

As far as what may cause this yes, possibly an actuator board (shorted driver) but more than likely electrical noise especially if the error is occuring intermittently:

1) Unplug the black PGND wire from the distribution board (just below and to the left of the 8 pin (green) heater connector). Make sure that it making a good, tight connection with the terminal. Then plug ot back in.
2) Check ground resistance from PGND to the chassis ground (< 0.5 ohms).
3) Check leakage current.
4) Reseat all of the boards in the card cage and check the mother board pins especially on the function and actuator boards.
5) Assure all the grounding straps are attached sucurely.
6) If the problem occurs regular enough turn the heater off (or disconnect the heater from the distribution board) and see if the problem reoccurs.
7) Check the distribution board for 'white' corrosion or other signs of damage. Note: I doubt that any corrosion could appear yet due to the fact that the machine is new.
8) Switch solenoids with another valve (maybe #26). Stray inductance?
9) Use a mag probe (to check valve #24's solenoid) and compare it to DIALVLO. When a conductivity or temperature alarm is present the solenoid should be 'dead' This will tell you if valve #24 is REALLY remaining energized. For example, if the solenoid is dead and DIALVLO = 1 the actuator board is okay the problem is noise or a bad function board.

I have never seen this failure. Have 1KOS machines.