Older Koldfront window and through the wall air conditioners included a drain plug that could be removed to assist with water drainage in excessively humid operating environments. Newer units DO NOT utilize any such drain plug. WAC and WTC Series air conditioners were modified to increase unit operating efficiency and as a result the drain hole / plug has been removed.
As water builds up towards the rear / back of the unit the fan blade will begin to splash / disperse that water over the coils which significantly aids in cooling of the internal components and increases the overall efficiency of the unit. If there is an over-accumulation of water, it will simply drain out of the lower back edge of the unit onto the exterior ground.
Provided that the unit has been installed properly with a slightly rearward facing slop as indicated in the instruction manual, there will not be any drainage issue with your unit. That slight rearward slope will allow any excess water to drain out the back of the unit. This same installation slope is required regardless of which unit you own or when it was purchased.
Window Air Conditioner Rearward Tilt
Through the Wall Air Conditioner Rearward Tilt
**Note: Rearward slope for though the wall sleeve is accomplished using the tapered foam blocks that are included with the Koldfront Wall Sleeve Model WTCSLV. If you are using an existing or alternative brand other brand