I have been receiveing a FLOW ERROR on a fresenius 2008H machine. I have checked numerous possible problems with not luck. This machine will pass TEST, RINSE, ACID RINSE and Chemical Rinse..But when A patient is running I recieve a FLOW ERROR. Not sure what is going on at this point, I have replaced to many parts to mention, maybe theres an expert here that has the million dollar answer, HELP, Tks

Flow errors can be one of the hardest problems to track down. I have had one cause by a bad o-ring on the deair oriface but that machine would fail PHT. It could be your V-43 o-ring or even a BC membrane. I imagine you have tried the obvious CFS transducer? Another freaky possibilty I have seen a couple times are worn DA or flow pump brushes even though the pumps calibrate fine.

Good Luck!

Tks Chuck, Yes, I have tried all the obvious possibilities as you mentioned except for the BC Membrane, Im starting to think I may have a tear or something to that matter. I often wondered if maybe I have an Intermittent problem with a flow motor that just quits running on its own,then starts back up, the brushes are new in both motors,,This is a weird one I must say, tks for the help..

I had a similar problem about 3 years ago on an H machine. It may sound a little to simple but here is what fixed it. I took another H machine and sat the two side by side. I traced the plugs wires on the distribution board one after another comparing the good machine to the bad machine. Finally I found that 2 balance chamber valves had gottent their plugs criss crossed some how during the early stages of trouble shooting this must have happened. Until I discovered this the machine would work fine for me and you could even dialyze on it for a day or 2 but eventually the problem would surface and you would see a very intermittent flow error. Good luck.

Thanks Mike, thats a new one for me, although I have worked on this machine many hours so I will check that out. My question would be if there were cables swapped or misplaced would it still pass PHT, Hmm I will check it out, tks again

Well it did pass PHT for me when it happened. Again I know it sounds a little to simplified but after working on a machine for a couple of hours and into the evening a couple of nights its actually prettly likely that two valves could get swapped. I guess it passes because at that moment when testing PHT maybe both valves are getting power like they should be. But then when in treatment finally the valves cycle wrong and you get the flow error. Another plus is even if its not the problem while taking the time to trace each line to its component you may come across the problem (crusty valve or something like that). Well again good luck.

A quick and simple way to troubleshoot the Balancing Chamber diaphrams is: put the machine in dialysis on 500 flow. Record the conductivity. then slowly turn the flow up. If the conductivity changes with the flow rate then there is a real good possibility that you have a small tear in a diaphram. Just a little trick, hope it helps.

Another way to find out if the BC membrane has a tear in it is to bring machine up in conductivity. Than take your lines from the shunt door out and put both of them in a bucket of acid. If there is a tear within about 30-45 second the conductivity will go sky high. This is the easiest way that I have found to check the BC membranes.

The most reliable way to check the BC membranes is to do a BC volume calibration. When the chambers switch the flow from the drain port should stop....if it continues to flow or trickle....the membranes are bad.

I would like to thank all of you for your input on this error, I have finally found the problem..I dont know why Fresenius doesnt call this a Flow Outlet Error, but V-30 the drain valve was being very erratic and not closing and opening like it should have..Everytime I would test the V-30 it would test to be good, Finally it stuck closed and caused pressure leaks on the balancing chamber which then was easy to trace back to it..So, after all that work, V-30 was the big problem..Intermittent problem that is,,lol, tks again everyone for all your help. Chief

Chief,

One of the weirdest error messages I have seen is on the Althin machines. The error message is "Power Supply Out of Range"...the part that is bad is the dialysate pressure transducer!!