H.Koenig BW1880 Manuel D'utilisation page 18

F. REPLACE WATER INSIDE THE COOLING CAVITY
It is recommended replacing the water inside the cavity once each
week. (No need to replace the water for each beer keg, one week
one time recommended)
Open the drain switch, water flow
into the S shape drainpipe from this
end
Water flow into drip tray from this end
1. Open the drain switch to drain out the water from the cavity into
the drip tray. Make sure the drip tray is fit into the notch to avoid
water flow to the desk; the drip tray can load 450ml water;
2. After all water drain out, close the drain switch and put 800ml fresh
water into the cavity.
3. Open the drain switch (drag the switch forward to 90 degree
angle), and drain out the water inside the cavity to drip tray, and
need twice to drain out the water..
Warning: 1）Clean water is necessary;
2) Make sure the drip tray is fit into the notch to avoid
water flow to the desk;
3) The drip tray can load 400-500ml water;
Figure 28(Sketch map of drain construction)
Move the drain switch to
horizontal line, will start to
drain water
Drip tray