solution intake failure

I may be wrong but, I don't think a Solution Intake Failure alarm would be issued by either ENDLF or BICLF. I think that comes from the Level Sensor in the Upline Tank not going HIGH when drawing in the citric acid. Nothing is going through the conductivity cells until the machine goes into Recirculation. Then if the conductivity is low (I believe < 3.0 mS/cm), the machine will alarm LF Too Low.

I will say Chuck is close but not close enough to get a kewpie doll, just a cigar. The disinfection process begins with a rinse out which turns into an "empty the upline tank" action. The level sensor must go LOW. That LOW will trigger the UF pump to start turning and then cause both VD and VZ (disinfect and recirculation valves) to open. VD is built similar to car tappets. When one tappet is open, the other is closed. The UF draws up the citric into the flow path when VD opens. The citric tubing has some air in it, so as the citric is being drawn up, that air will cause an air bubble to get caught in the red dialysate tubing. FPA is spinning, so it pulls the citric/water mix into the air separator. The system uses the lower and upper level sensors of the air separator to determine if sufficient fluid has been pulled in. In the meantime, with VZ open, FPA is pushing the fluid into the upline tank so that level sensor will change from LOW to MEDIUM. The stroke value of UFP gives the computer an idea of approximately the amount of fluid that has been pulled in. The air separator shows if it was achieved and if there is agreement, the UFP stops, VVBE opens to fill the upline tank to high, and then CIRCULATION begins.

Where things can go wrong? Rinse bridge has a leak (I have seen both internal and external). VD valve O-rings need replacing (repair kit for both and don't forget to use O-ring grease, especially on the eccentric cam O-rings. Disinfection port under the rinse bridge is not providing a seal with the tubing. I have seen build-up around the barb so that it allows air to be pulled in; the tubing not being exchanged as needed and is too loose on the barbed port; and the neck of the port is corroded (dull grey) to the point that it allows air to infiltrate). All this results in a growing air bubble in the red dialysate line. Again, if too much air gets drawn in, the sensors do not see sufficient fluid and the infamous alarm is issued.

Two other options: crystalized citric in the tubing or in the port entrance blocking the draw up.

TIP: NEVER use a needle to clear the port. Bend the short leg of a small paperclip out a little to clear any dried citric from the port entrance.

B Braun 50% citric, when mixed with the liquid in the machine should result in a conductivity value during recirculation from 3 to 5 mS/cm. There is a MINIMUM value of 2.2 mS/cm. If that is reached during the disinfection, you are probable losing fluid to drain and will need to find the cause. Both the BICLF and ENDLF should be about the same reading during recirculation.

This sounds like the concentrate tubings are reversed. The acid wand goes to the LEFT fitting under the door; the bicarbonate goes to the RIGHT fitting. On the inside, the left fitting goes to the leftmost piston pump (KP: bottom right port); the right fitting goes to the rightmost piston pump (BICP: bottom right port). As seen from the front of the machine, the DF shelf has the DF MANIFOLD mounted to it. In the upper right corner are two barbed fittings. The fitting to the right is the bicarbonate input to the manifold, and that tubing should trace back to the bottom left port of BICP. And the fitting to the left is the acid input to the manifold and that tubing should trace back to the bottom left port of KP. UNLESS you accidentally put your bicarb wand into a jug of acid!!! to get those 17/5 values. But something is still not right because even if BICLF WAS 17, the ENDLF SHOULD ALSO READ 17. Unless it was totally miscalibrated, or something else is wrong. Does that make sense to you?

Hope this helps.

Makes sense mostly. biclf and endlf are dummy proof connectors and each was replaced separately not at the same time too but mine came with the connectors already installed so no chance of swapping connectors anyway, I did a calibration following the manual each time...I did the common calibration for conductivity.

I will say on both machines at first the citric acid draw was sluggish...I connected a 60cc syringe with citric and pushed and then it began to pull citric much more...I was hoping it was just an air lock. I reconnected the line, rinsed, then restarted and it pulled correctly but still gave the error immediately after closing the disinfect valve on both machines. Both machines are showing a LOT of air from the red dialyzer quick connector which is why I'm suspecting the rinse bridge on both. On both the red dialyzer quick connector is on the left and blue on the right on the bridge. The acid/bicarb wands on both are placed correctly too. On my other machine that disinfected correctly it pulled a little air through the red dialyzer connector but after it pulled it through there was no more unlike these two which is constant air and a trickle of fluid.

I'll rebuild the rinse bridge and report back thanks for the tips!

I would probably suspect the air separator seals as being the source of the air.

And I say the O-rings on the eccentric cam are worn and letting a lot of air seep in because of the pull from the UF pump.