I want to leave my DEC 21A on with the continuous external draining function while away for vacation. Your manual page 6 section B say I have to drill a hole through the drain spout before connecting the supplied drain hose. My concern is, as I cannot see how far in should run the drill bit and can see where the drilled out plastic debris go, how can I be sure I would not over drill and the plastic debris would not plug up the drain. Thanks for you advice Ross Lau