Ralf,

Interesting observations/questions… I went through the same questions/thought processes. I used a larger reservoir for the water collector…an old peanut butter jar to be exact. You’ll collect water in the a/c evaporator at low altitudes/on the ground, but little, if any above 15,000’…the air is relatively dry and cool up there, so the capacity needs to account for ground and expected low-altitude ops. My PB jar fills up in about half an hour in damp ops at low altitude.  Like you, I found that a nylon fitting, used as a seal, allowed a small amount of leakage…water or air. The air leak has not bothered the pressurization system, and it helps keep the reservoir empty. Give this a try.

You can get some surface tension blockage with a 1/4” line. Two considerations. The cabin pressure is normally higher than ambient/outside, so you’ll normally have just a small amount of air flow through the drain line, helping the water flow. Also, a drop of liquid soap in the evaporator collection tray breaks the surface tension and allows the water to flow freely. (It also cleans the line… J ).

Last point: During normal operation, the pressurized cabin puts a pretty good “seating” load on the float ball. Mine is smaller than Jeff’s; probably about the same size as yours (?...hard to tell from the picture). This is fine, as the reservoir holds the collected water until you land/depressurize. I found, however, that the float ball would sometimes stick and not drain the water after the cabin was de-pressurized. A sharp tap or puff on the drain line exit causes it to open and drain as intended.

I  installed my condensation collector/valve assembly in the back of the cabin pressure controller cavity…in the rear seat bottom… and drained it through a short piece of hose through the bottom of the fuselage. I would not just dump the water in the lower fuselage…there is more than you’d think, and the water will cause corrosion and other problems over time…

My two cents…

Bob P