Since in this system the evaporator is always filled with liquid refrigerant, this is also considered a flooded system.
During the run cycle, liquid refrigerant is forced into the high-side float chamber through the condenser. As soon as enough liquid refrigerant enters the float chamber, the float ball moves up allowing the refrigerant to flow to the evaporator. Because the evaporator is under low pressure, the line entering it should be insulated. Often a capillary tube is used on the line connecting the high-side float chamber and the evaporator. If not, a weight valve should be installed to prevent the liquid from evaporating in that connecting line.
Refrigerant enters the evaporator under low pressure, evaporates and absorbs heat from the evaporator. It then flows through the suction line into the compressor where it is forced out under high pressure into the condenser again. The condenser then removes the heat absorbed in the evaporator, changing the vapor refrigerant back into its liquid state before it is forced into the float chamber to repeat the cycle. NOTE: The amount of the refrigerant charge in a high-side float system must be measured very accurately for the proper operation of the unit.
Liquid receiver tanks are used on all units with a high-side float system. Units with capillary tubes use an accumulator (installed at the outlet of the evaporator). The motor-control, temperature-sensing element is installed on the coil just before the accumulator on the suction line.
Liquid receiver tanks are used on all units with a high-side float system or systems using an expansion valve(s). Systems with capillary tubes use an accumulator, which is installed at the outlet of the evaporator. The motor-control, temperature-sensing element is installed on the coil just before the accumulator on the suction line.