I have a B/Braun Dialog Advanced machine that overflows into vent line during citric/thermal procedure. The fluid vents every few minutes, usually about 10ml at a time.

I have changed out the following parts:

1. Level Sensor Assembly.
2. RVVB.
3. DMV.
4. Calibrated TSE. (in case out of cal. causing boil over)

After replacing DMV, I tried to calibrate to 1.3 bar. The pressure gauge needle vibrates very hard, from 0 - 2.5 bar. Even when the machine is turned off RVVB will still vibrate wildly and not stop until the water supply is turned off. I made sure DMV and RVVB were installed in the proper flow directions.

Does anybody know what might be causing this problem?

Thanks in advance.
-Steve

I had a machine do this a couple of months ago. I replaced all of the same parts that you have. It ended up that the new DMV that I put in was faulty. These DMV's really aren't that great. The pressure was building and pushing past the RVVB. IT was doing the same thing as your machine, leaking in the disenfect cycle and when the machine is off. If you have another DMV I would replace it again. It could be the same problem.

Thanks BB Teck, I'll try another DMV on Monday.

Steve make sure that the electrical connections are properly connected.

Installed four brand new RVVB's, but had the same problems described above. Called in B/Braun tech support. The field service tech installed his new RVVB and had the same problem. He had an old RVVB in his tool kit. We installed it and guess what? It worked!

Beware, new RVVB's! I inspected the springs and plungers on defective ones, but could not see defect. I will send them all back to B/Braun for analysis.

The Dialog Advanced manual states the DMV pressure to be set at .9 bar not 1.3 like the plus machines. Also there is a small plastic flow restrictor in the tubing past the RVVB valve check and make sure it is still there.

The B/Braun technical training class taught 1.3bar. RVVB has a restrictor built into the barbed fitting at the inlet flow side.

I can assure you that Steve Meyers from B Braun will tell you that the Advanced Manual clearly states under TSM Service Program page 4-125 that RVVB is to be set to .9 with a tolerance range 0.7-1.0bar on the Advanced machines. I have been working on the Braun machines since 1998 and this has been an issue for some of my techs that are new and are being crossed trained at Braun for both the Advanced and Plus machines. As far as the restrictor goes yes the newer machines have the restrictor in the barbed fitting but older Dialogs/Dialog Advanced had a small white plastic reducer in them that can degrade over time the part number for this is 34570306.

Do not want to argue, but learned the 1.3 bar calibration from the technical training class, which had Steve Myers as one of the instructors. It has been about five years since the class, but remember one of the instructors saying that dmv USED to be set at a lower pressure.

The B/Braun preventive maintenance guide sent home with the students also reads to set DMV at 1.3 Bar.

The field service tech that came out also set the dmv to 1.3 bar.

I am sure that 0.9 bar will work alright, but if you want the LATEST info call the technical service number to confirm.