Copyright Goodheart-Willcox Co., Inc. Chapter 32 Residential Split Air-Conditioning Systems 803 10 Fan Control panel Heated air Compressor Ambient air Liquid line connection Suction line connection Lennox Industries Inc. Figure 32-8. To condense and subcool the circulating high-pressure refrigerant, a central air-conditioning condensing unit draws in ambient air through the sides of the unit and discharges it out of the top of the unit. Control board Service valves Reversing valve Accumulator Compressor Tempstar Figure 32-9. Note the location of the reversing and the service valves in this cutaway view of a heat pump. A technician can attach a manufacturer-supplied control reader to the control unit to obtain system performance data.