In the process of replacing a Carrier Air V with a Coleman Mach 15,000 BTU if the technician ever brings it over and helps me lift it up on the roof.
The Drip pan does not have actual "Drain holes" what it has is a "Drip Lip" it is designed to hold a level of water for two reasons
1: To act as a water trap and prevent insects from entering via the drain channel
2: to aid in cooling (The drip pan runs under both the Evaporator AND the condenser coils, evaporation of water is very very efficient when it comes to cooling)
Two things I have found that cause either a light "Rain" or NIagra Falls (the latter when the fan shuts off) are
ON my Carrier's the "Drip Lip" is on the rear of the beast, past the condenser coils. if the FRONT of the RV is a bit low, the FRONT of the drip pan may be lower than the lip, and thus it drips inside (naturally) (On my Advent it's on the Driver's side by the way, Do not know where Coleman put theirs.....yet.)
IF the INTAKE filters get dirty, then the blower sucks hard enough to vacuum the water out of the tray and hold it in front of the evaporator coils. When the fan shuts off all this water it's been holding in suspension... FALLS (Niagra Falls)
Keep the filters clean, Level well. And enjoy the A/C while it lasts
