A remote system designed for home or commercial installation can be obtained with a complete package. It has the condensing unit, correct operating refrigerant charge, refrigerant lines, and evaporator unit.
The charge in the line makes it important to have the correct size of line for the installation. Metering control of the refrigerant in the system is accomplished by the exact sizing (bore and length) of the liquid line. The line must be used as delivered. It cannot be shortened.
Lennox has the refrigerant flow control (RFC) system. It is a very accurate means of metering refrigerant in the system. It must never be tampered with during installation. The whole principle of the RFC system involves matching the evaporator coil to the proper length and bore of the liquid line. This is believed by the manufacturer to be superior to the capillary-tube system. The RFC equalizes pressures almost instantly after the compressor stops. Therefore, it starts unloaded, eliminating the need for any extra controls. In addition, a precise amount of refrigerant charge is added to the system at the factory, resulting in trouble-free operation.
The condensing unit is shipped with a complete refrigerant charge. The condensing unit and evaporator are equipped with flared liquid and suction lines for quick connection. The compressor is hermetically sealed.
The unit may be built in and weatherproofed as a rigid part of the building structure. See Fig. 15-20. The condensing unit can be free-standing on rooftops or slabs at grade level.
Figure 15-21 shows the condensing unit designed for the apartment developer and volume builder. It comes in 1-, 1.5-, and 2-ton sizes. Cooling capacities range from 17,000 through 28,000 Btu. An aluminum grille protects the condenser while offering low resistance to air discharge. The fan is mounted for less noise. It also reduces the possibility of air re-circulation back through the condenser when it is closely banked for multiple installations. When mounted at grade level, this also keeps hot air discharge from damaging grass and shrubs.