828 Copyright Goodheart-Willcox Co., Inc. Chapter Review Summary • Split air-conditioning systems usually fall into one of two categories, including central air-conditioning systems and ductless air-conditioning systems. • A split system has its condensing unit outdoors and its evaporator indoors. • Heat pump systems are split systems that can provide both cooling and heating. A reversing valve changes the flow of refrigerant. • Comfort cooling systems are equipped with operating controls and safety controls. Operating controls, such as thermostats, pressure switches, humidistats, motor starters, and relays, regulate the normal operation of the system. Safety controls monitor conditions and shut off the system or specific components to protect system components and building occupants. • A single combination heating and cooling thermostat is often used in central air-conditioning systems. In some systems, a humidistat controls the relative humidity in the conditioned space. • A central air-conditioning system includes a single evaporator installed in a central air handler cabinet that is connected to a network of ducts. • Installing central cooling onto an existing furnace is done in four steps: installing the condensing unit, mounting the evaporator, installing the refrigerant lines, and making the electrical connections. • Servicing a central air-conditioning system begins with a check of the system’s general condition. During this inspection, check for leaks, malfunctioning controls, and moisture-related problems. Fans and motors should be cleaned and lubricated, worn belts should be replaced, and the condenser and evaporator coils should be cleaned. Record any service work in company records and system records for the home owner. • A ductless split system is a split air-conditioning system that does not use forced-air ductwork as a means of distributing cooled air. These systems have an outdoor unit and one or more indoor units connected by refrigerant lines. Air is circulated in a given space by an indoor unit’s fan and cooled by the evaporator. No air ducts are used. Review Questions Answer the following questions using the information in this chapter. 1. A _____ air-conditioning system uses a single indoor unit connected to a duct system. A. ductless B. mini-split C. central D. VRF 2. Heat pump systems include a(n) _____ that changes the flow of refrigerant. A. thermostat B. reverse valve C. evaporator D. humidistat 3. Which of the following is not considered a type of safety control? A. Oil pressure controls. B. Electrical fuses. C. Inverters. D. Internal motor overloads. 4. A(n) _____ controls comfort cooling. A. air handler B. humidistat C. refrigerant pressure control D. thermostat 5. A standard split system that provides central air- conditioning includes which one of the following system components? A. An air handler. B. A chiller water pump. C. An inverter. D. A Y tube. 6. An air-cooled condensing unit should be installed _____. A. beside a building along an inside corner with two outer walls no more than 3″ away B. beyond a building’s roof overhang and eaves C. inside a well-insulated and unventilated room within a building D. tightly surrounded on all sides by tall, thick bushes