Reagent is drawn a drop every 1.5 seconds. You can imagine how slow that creeps up. THAT is the reason why we recommend not extending the line too much. Only use what you need and do not loop because the longer the line is, the longer it will take for it to prime.
You can place a cup next to the KHG but if the line is long and looped, it will take just as long as if you place the cup away from the KHG and stretch out the line.
Just be patient and it will start to drop into the chamber. Out of all the units we have sold, I have YET to see one unit where the KS does not work. It just takes a long time to prime because of the length of the line.