No, window unit air conditioners, also known as room air conditioners, do not require draining before charging. These units typically use a refrigerant, such as R-410A or R-22, to cool the air. The refrigerant is contained in a closed system, which circulates through the air conditioner to absorb heat from the indoor air and release it outside.
If your window unit air conditioner is not cooling properly or is not functioning as expected, it is recommended to consult the manufacturer's instructions or contact a professional technician who specializes in air conditioning systems. They can diagnose and address any issues with the unit, including checking the refrigerant levels and performing any necessary maintenance or repairs.