Marine Air Conditioner Condensate Drain Slope
The short answer
A continuous gravity fall from the drip tray to a sump or shower drain — never to the bilge. A 16,000 BTU unit pulls litres a day out of humid air, and any rise, sag or loop in the hose holds water and backs the tray up until it overflows.
Boat Air Conditioner Condensate Drain Slope — Requirements and Limitations
"It drains to the bilge" means you have bought a machine that fills your bilge with fresh water all summer, which is how bilges start to smell and how bilge pumps wear out. Re-plumbing to a sump costs a few hundred dollars and is worth every cent.
Boats also sit bow-down at rest more often than people expect, so a tray that is level alongside may not be at anchor. Check the fall in the attitude the boat actually floats at.
Related Sizing, Installation and Service Guides
Each of these answers a different part of the same problem.
- when it ends up in the bilgethe diagnostic path and the fixes
- flushing the drainthe annual job that keeps it clear
- the drain line on a quotea $120–400 item, left off constantly
- why a blocked drain smellsthe same slime, two symptoms