A/C Drain Kit
Our AC condensate would drain out on to the roof and find its way down to the ground from the two side “gutters”. The gutters ended a few feet before the end of the coach which resulted in water streaks, generally on the tail end. The water streaks discoloration is unsightly and the deposits can be very hard to remove with polishing.
Dometic makes an AUXILIARY DRAIN PAN KIT (3107688.016) that captures the condensate and directs it to a drain system. The kit was specifically designed for Dometic Penguin, Brisk Air, and High Performance series air conditioners/heat pumps. This kit is really designed to connect to an existing internal drain piping, this is common on some trailers, such as airstream, and on newer Foretravel coaches, stating in ~2006. You can find them on Amazon: DOMETIC Drain Kit
Since our coach does not contain the needed internal roof plumbing, other arrangements had to be made to funnel the collected condensate to the back. MOT installed our drain cups pointing outward so their output could be connected to a roof mounted drain line. This new drainline runs the length of the roof and then drops down inside the rear endcap. Inside the endcap the drain line continues down to the ground. This allows all the condensate to drain our behind and below the coach, no more water stains!
One alternative approach would be to drain the line down behind the refrigerator, where there is an existing drain line at the base. On our coach this would have place the water output center patio, leaving for a nice puddle right where you are sitting. For other coach arrangements this may work, assuming you can get everything to flow to where its needed.
Some Lessons
The drip trays that come with the kit are not UV stable. Under normal conditions this may not be an issue, but since ours were reversed, the outlets (where the drain hose connects) were exposed to the sun. We found they deteriorated and became very brittle in under a year with a couple of them needing replacement. Eventually we had to replace all of them (since we had to replace a failed A/C unit), the new set we painted with UV resistant paint and so far they have held up well. Adding an additional sun shield / shade would also be a good idea.
The double stack of gasket (supplied with the kit) compresses a lot, you need to make sure its not so much that the drip trays end up in direct contact the roof. If this happens you will get more noise and you run the risk of cracking the outlets.
The double stack of gasket at the back of the unit sags the most. There is a lot of weight cantilevered off the back so those rear strips take a lot of load. Keep an eye on them and replace / shim as needed to keep the units level on the roof. Most of the gasket compression happens in the first couple of months.