Copyright Goodheart-Willcox Co., Inc. 808 Air-Conditioning Systems 32.4.3 Installing Refrigerant Lines The suction and liquid lines between the condensing unit and the evaporator coil may be connected with flared con- nections, brazed connections, or quick-connect couplings. The flared and brazed connections were discussed in Chapter 8, Working with Tubing and Piping. Quick-connect couplings are discussed later in this chapter. Refrigerant lines should be kept as short as possible. The proper diameters for the refrigerant lines are determined by the size of the condensing unit and the length of the lines to connect the condensing unit to the evaporator. If the system is being installed in a hot, humid climate, the manufacturer Condensate Drainage Check the local building code for condensate drainage requirements. In some installations, a drain pump must be installed to remove the condensate to the outdoors. Code Alert may recommend a larger diameter than would be recom- mended for a more temperate climate. Always follow the manufacturer’s sizing recommendations. Many condensing units are installed at a higher eleva- tion than the evaporator. Therefore, a U-bend should be put in the suction line to assist in oil return. The suction line should slope downward slightly toward the condens- ing unit. It should also be insulated. If the suction line is Brazing Refrigerant Lines If the refrigerant lines are to be connected by brazing, remove the Schrader valve cores from the service valves before brazing the lines to the stubs. If the valve cores are not removed, heat from the brazing process will damage the rubber and plastic parts in the valve core. Also, wrap the service valves with a wet cloth before brazing the joints. This will protect the valves from overheating. Caution 6"(a) Furnace body Blank-off plate Z-formed blank-off plate Coil cover plate Plenum cutout Evaporator Blank-off plate (a) Where bonnet is appreciably wider than 12", provide at least 6" between bottom of coil assembly and top of furnace. Goodheart-Willcox Publisher Figure 32-17. A slant evaporator installed in a furnace plenum. The blank-off plates support the coil and direct all air through the evaporator coil.