Full charge means the amount of refrigerant required for normal operating characteristics and conditions of the appliance as determined by using one or a combination of the following four methods:
(1) Use of the equipment manufacturer's determination of the full charge;
(2) Use of appropriate calculations based on component sizes, density of refrigerant, volume of piping, and other relevant considerations;
(3) Use of actual measurements of the amount of refrigerant added to or evacuated from the appliance, including for seasonal variances; and/or
(4) Use of an established range based on the best available data regarding the normal operating characteristics and conditions for the appliance, where the midpoint of the range will serve as the full charge.