White filter in the internal overflow tube not necessary
There is a white filter (approx. 4 mm x 5 mm in size) in the inner venting and overflow tube of the KHD.
This filter lets air through but not water.
The purpose of this filter is on the one hand, to reduce noise during the measurement from inside the KHD, on the other hand, it should avoid that in case of unintentional overfilling of the measuring cell, e.g. due to incorrect calibration of the pumps or incomplete emptying of the measuring cell before the next measurement, water comes out of the the venting (also overflow) outlet.
However, there were cases in which the filter clogged, possibly by overfilling with (dirty) water, which then led to incorrect measurement results.
Therefore, we came to the conclusion that the filter can be rather counterproductive: The minimal louder operating noise and the possibility that water comes out of the vent outlet is not considered to be problematic.
That means:
1. KHD will be produced from now on without this filter.
2. If problems occur with the KHD that indicate a clogged vent tube, please remove this filter without replacement.
You are welcome to send it to GHL for removing the filter, or you can do it by yourself.
