The tall water chilling unit with the water service large bottle of water on top may have a problem.. When I removed my last empty bottle of water, it came off very hard, and the plastic plug that is supposed to pop into the bottle when you stick your full bottle on top was still afixed to the center prong of the base. I had to cut it off. The new bottle is on now, and I don't see that center plug for that bottle inside anywhere so I will bet that plug is stuck to the center prong.. Either my unit's prong has developed a problem, or the water service by Edelweiss is using plugs of an incorrect size. - Nothing worse than getting your prong stuck when you try to pull it out, is there?