Dometic 3107688.016 Auxiliary Drain Pan KitDometic 3107688. 016 Auxiliary Drain Pan Kit This kit is recommended for use with most air conditioners when choosing to drain condensation to a 1 2" ID drain tube. Many Airstreams have a drain tube in their walls for this application. If you are restoring a riveted trailer and intend to use an air conditioner, we highly recommend installing the in wall drain tube. Allowing an air conditioner to drain onto the roof will cause water streaks on your