We had some customers who got wrong or no measurements with the KH Director.

Meanwhile, we have found the cause: KHD dirty inside, especially the internal circulation pump.

The tricky here is: The circulation pump seems to be running, only on closer inspection can be seen that the flow generated is much too low to get a good reading.

Please note our instructions:

The sample water tube must always take water from an area free of sediment and dirt! Dirt and/or sediment will damage BOTH the dosing pumps and internal circulation pump inside the KHD! In these cases, the KHD will no longer provide a correct measurement. The water sample tube must be positioned carefully so that only clean water is pumped into the KHD.

If dirty sample water cannot be prevented, a filter must be installed before the water sample pump!

(we also included these instructions in the new KHD manual, dated 14. Aug. 2018)

If it has already happened that the pump is dirty: you can open it and clean it inside, then it works again.
When doing this: Be careful - No water must touch the electronics inside the KHD