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Post by dialysisbob on Dec 15, 2023 6:51:46 GMT
Hello All,
I have bluestar machine that has 23k hours and I keep calibrating the condo and bicarb and condo cells because the conductivity is off, its jumping between 13.7 - 13.8.
For example the TCD is 13.3 and I am getting 13.7 - 13.8. Machine has new acid and bicarb pumps, new membranes, tried both cfs 10 and 9. recalibrated acid and bicarb and condo cells like 5 times and results are the same.
Any ideas what is causing this?
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stuff
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Post by stuff on Dec 15, 2023 13:27:52 GMT
My reply is assuming the machine is a non bi bag.
If you plug your acid into a jug does your conductivity come down?
What is the pressure on your acid loop? You can use the yellow loading pressure gauge to check this.
The Fresenius machines(except bibag) are designed to see a 2 psi max. If this is exceeding acid actually pushes its way into the machine causing your conductivity to be higher.
How to fix this; 1. You can install regulators at each wall box. This is a PIA and expensive 2. back at your acid tank you can install an over regulator circuit. This basically lets the acid either flow to the loop or back in the tank, by adjusting valves you can adjust your loop pressure 3. Run on jugs
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Post by ThereAreSomeWhoCallMeTim on Dec 15, 2023 16:05:43 GMT
You can try recalibrating the acid and bicarb pump volumes, also check to see if the balancing chamber volume is off. The volume should be written on the chamber itself. You can go into calibrate and verify that the volume on the chamber matches the volume on the calibrate screen.
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Post by dialysisbob on Dec 15, 2023 17:05:15 GMT
My reply is assuming the machine is a non bi bag. If you plug your acid into a jug does your conductivity come down? What is the pressure on your acid loop? You can use the yellow loading pressure gauge to check this. The Fresenius machines(except bibag) are designed to see a 2 psi max. If this is exceeding acid actually pushes its way into the machine causing your conductivity to be higher. How to fix this; 1. You can install regulators at each wall box. This is a PIA and expensive 2. back at your acid tank you can install an over regulator circuit. This basically lets the acid either flow to the loop or back in the tank, by adjusting valves you can adjust your loop pressure 3. Run on jugs I forgot to mentioned that this is a bibag machine.
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stuff
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Post by stuff on Dec 15, 2023 17:55:30 GMT
You can try recalibrating the acid and bicarb pump volumes, also check to see if the balancing chamber volume is off. The volume should be written on the chamber itself. You can go into calibrate and verify that the volume on the chamber matches the volume on the calibrate screen. For whats its worth the 8 balance chambers I have ordered over the past year did not have this written on them. Bibag from what I am told has ways to regulate pressures inside the machine so loop pressures do not mess it up. Not really sure as I do not have Bibag and can not help on that end
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pacnw
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Post by pacnw on Dec 15, 2023 18:19:15 GMT
You mentioned you did the condo cells.... Did you also do the condo confirmation cell calibration using the yellow data cord and dongle?
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Post by dialysisbob on Dec 15, 2023 18:56:18 GMT
You mentioned you did the condo cells.... Did you also do the condo confirmation cell calibration using the yellow data cord and dongle? no
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Post by just a BioMed on Dec 15, 2023 22:24:38 GMT
Trying calibrating the acid and bicarb pumps with 10 strokes instead of the standard 30 that it defaults to.
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Post by dave74 on Dec 16, 2023 3:35:59 GMT
Trying calibrating the acid and bicarb pumps with 10 strokes instead of the standard 30 that it defaults to. How does this help? I've always calibrated by the book.
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Post by just a BioMed on Dec 16, 2023 14:56:18 GMT
Trying calibrating the acid and bicarb pumps with 10 strokes instead of the standard 30 that it defaults to. How does this help? I've always calibrated by the book. While normally a by the book kind of person. I've had several machines where I spent days calibrating with 30, conductivity cell replacement, conductivity cell calibrations, temperature calibrations even though they were on the mark, flow deair and loading dead on, no balancing chamber issues, pump rebuilds, pump calibrations, and nothing worked. The only thing I could get to work on the machines was calibrating at 10 strokes. Conductivity almost dead on for pre and post cells, matching direct to the 90xl that was verified with 14.0 solution. Again I don't normally go off the book, but this actually something that worked for me. Thank you for defending the true procedures, I do appreciate that and support it.
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Post by Chuck Weddle on Dec 16, 2023 15:26:22 GMT
Using a lower volume will make the measurement less accurate. That's how they are able to measure culture and endotoxin levels to "ultrapure" levels....A much larger sample is processed.
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Post by dave74 on Dec 16, 2023 15:54:06 GMT
In a different thread, a member hinted that some biomeds fudge the volume numbers to get the conductivity closer the TCD.
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Post by brocklee on Dec 18, 2023 16:52:53 GMT
Hello All, I have bluestar machine that has 23k hours and I keep calibrating the condo and bicarb and condo cells because the conductivity is off, its jumping between 13.7 - 13.8. For example the TCD is 13.3 and I am getting 13.7 - 13.8. Machine has new acid and bicarb pumps, new membranes, tried both cfs 10 and 9. recalibrated acid and bicarb and condo cells like 5 times and results are the same. Any ideas what is causing this? We have been having this problem for quite a bit on some of our bibag machines, and really haven't found a solid solution. it seems to have really showed up after doing our bluestar upgrades, although that could just be coincidence. The one thing that has really come to my attention over the last year or two, is that our 90xl condo sensors only hold good calibration for around 6 months tops. Checking and switching them has solved a couple problems with conductivity. I have one here at the shop currently and hopefully can get some insight here and/or provide my own in the near future.
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BMF
Junior Member
Posts: 86
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Post by BMF on Dec 18, 2023 19:57:41 GMT
As mentioned earlier, check you BC volume. The proper way to check the actual volume is to use a scale capable of reading grams. 1 gram equals 1ml so it is very easy to get an accurate BC volume zeroing out the collection device first, then after collecting the two BC squirts, weigh your sample and you'll have your true volume. This procedure is posted on p.407 of the troubleshooting guide.
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stuff
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Post by stuff on Dec 19, 2023 16:04:41 GMT
In a different thread, a member hinted that some biomeds fudge the volume numbers to get the conductivity closer the TCD. This is used to compensate for loop pressures, which a bibag machine should be doing anyways so fudging is not needed. You can tell if your loop pressure is the issue by using jugs instead of the loop.
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