Copyright Goodheart-Willcox Co., Inc. Chapter 32 Residential Split Air-Conditioning Systems 809 10 not insulated, moisture from the air will condense on the outside of the suction line and drip. An uninsulated suction line would also absorb additional heat from unconditioned space, which will need to be rejected at the condenser. As a result, system efficiency will decrease, and the compressor will not be cooled as effectively. A filter-drier and a sight glass should be put in the liq- uid line. The refrigerant lines should be supported and free of kinks and sharp bends. Any openings for the liquid and suction lines in the plenum and the building’s wall should be sealed with weatherproof, nonhardening sealing com- pound and tape. Once refrigerant lines are installed, check the refriger- ant lines and evaporator for leaks. Repair any leaks. Evacu- ate the refrigerant lines and evaporator. Next, charge the system with refrigerant. If the condensing unit is pre- charged, the isolation valves are opened and the charge is allowed to fill the system. If the condensing unit did not come precharged, the proper charge must be weighed in. General leak testing, evacuation, and charging procedures were described in Chapter 11, Working with Refrigerants. Always follow the manufacturer’s recommendations. 32.4.4 Installing Electrical Wiring The wiring requirements for central air-conditioning sys- tems vary from system to system. The electrical installa- tion must be completed as shown in the wiring diagram furnished with the system. The wiring requirements usu- ally consist of providing a 240 V connection to power the condensing unit and a 24 V connection from the thermo- stat to control the condensing unit. The 240 V circuit is equipped with an electrical disconnect so the system can be quickly disconnected for service, Figure 32-18. Liquid Line/Capillary Tube Installation Some systems use the liquid line as the capillary tube. Larger-bore (ID) tubing reduces the chance of clogging from dirt or moisture. To ensure proper operation, do not shorten or lengthen a combination liquid line/ capillary tube during installation. Caution Disconnecting Means According to the National Electrical Code, a condensing unit’s electrical disconnecting means must be within sight from the condensing unit’s location and also readily accessible. Within sight means that the disconnect can be no more than 50′ away. Readily accessible means that personnel will not need to climb, use tools, or remove obstacles to reach the disconnect. Code Alert When installing wiring that is to be exposed to out- doors, check that its insulation is properly rated for such use. Outdoor use means that the wiring will be exposed to moisture from precipitation and also to the powerful rays of the sun. Not all wiring is intended to withstand such exposure. 32.4.5 Installing Assembled and Charged Systems Sometimes a split system is ordered completely assembled and charged. It will include the condensing unit, evapora- tor, controls, and tubing. The complete assembly is shipped as a single package. The tubing needed is usually wrapped around the evaporator. Work required at the point of installation includes the following steps: 1. Uncrating and carefully unwinding the tubing from the evaporator. 2. Installing the condensing unit and evaporator in their proper places. 3. Making the necessary electrical and control connections. Electrical Wiring Electrical circuits must be installed in accordance with local building codes, which often specify that work be done in accordance with the National Electrical Code. Consult your local electrical utility concerning the primary service capacity. Code Alert Goodheart-Willcox Publisher Figure 32-18. Electrical disconnect box. Note that the pullout contact can be pulled out or flipped upside down to disconnect the condensing unit so it can be serviced.