HVAC Quiz Chapter 21,22,23, & 24. Questions & Correct Answers 2024-2025. Graded A+, Exams of Refrigeration and Air Conditioning

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HVAC Quiz Chapter 21,22,23,

& 24. Questions & Correct

Answers 2024-2025. Graded

A+

____ is the best method of checking to see when a refrigerant coil has a proper level of refrigerant. - ANSSuperheat A bolted together motor-compressor assembly is sometimes referred to as a semi-hermetic type. - ANSTrue A normally operating water- cooled condenser is operating with a 10° differential between water in and water out. If scale forms on the water tubes and the entering water is 85°F, which of the following is possible? - ANSThe outlet water temperature will be lower than expected. The system head pressure will rise. A normally operating water- cooled condenser is operating with a 10° differential between water in and water out. If the amount of 85°F water going through the condenser is reduced, which of the following is a possible temperature of the water leaving the condenser? - ANS105°F A refrigeration system designed for the storage of flowers or candy is considered a ____ type. - ANShigh temperature A stamped plate evaporator usually does not use a fan to move air across it. - ANSTrue A thermostatic expansion valve controls refrigerant flow to the evaporator based on ____. - ANSevaporator suction line superheat A typical

evaporator operating temperature in an air-conditioning system is ____. - ANS40°F A typical superheat for an evaporator operating under normal conditions would be ____. - ANS8 to 12°F An air-cooled condenser that is operating in a climate that has four distinct seasons must ____. - ANShave some type of head pressure control Balanced port TXVs are used to ____. - ANSfeed refrigerant at a normal rate with low condenser entering air temperatures Because a scroll compressor's has fewer moving parts, it operates much quieter than other compressor designs and technologies. - ANSTrue Condensing temperatures in an air-cooled condensing unit can be reduced by ____. - ANSincreasing the condensing surface area increasing the cfm through the condenser decreasing the temperature of the air entering the condenser Evaporators that are operated full of liquid and are equipped with a device to keep the liquid refrigerant from passing to the compressor are known as ____. - ANSflooded evaporators High head pressures from low ambients can cause insufficient refrigerant flow rates through metering devices, which in turn starve evaporators - ANSFalse High-temperature refrigeration applications will normally provide box temperatures of ____. - ANS47 to 60°F If a thermostatic expansion valve's thermal bulb came loose from the suction line at the outlet of the evaporator, which of the following could result? - ANSThe bulb pressure would increase

and the thermostatic expansion valve would open. Liquid refrigerant would flow back to the compressor. The superheat in the evaporator would decrease If an R-12 refrigeration system has its air-cooled condensing unit on a 100°F roof and the condenser outlet temperature (refrigerant) is 115°F, with how much subcooling is the condenser operating? - ANS15°F If the application requires a coil design to operate below freezing, there must be provision for ____. - ANSdefrost If the spring pressure of a water regulating valve is increased, the system head pressure will also increase. - ANSTrue In a water-cooled condenser with dirty condenser tubes, the temperature difference between the refrigerant and the leaving water will be ____ when the tubes are clean. - ANSgreater than Liquid entering the compression chamber of a reciprocating compressor can lead to ____. - ANSboth a and b Mineral deposits in the water portion of a water-cooled condenser act as ____. - ANSan insulator Most of the heat energy in the suction vapor entering the compressor is ____. - ANSsuperheated from the evaporator Rotary compressors are used primarily in ____. - ANSsmall commercial refrigeration units SEER is calculated based on the total amount of cooling (in BTU's) the system will provide over the entire season, divided by the total number Watt-Hours it will consume. - ANSTrue The ____ in a refrigeration system is responsible for

absorbing heat into the system from whatever medium is to be cooled. - ANSevaporator The ____ of the liquid refrigerant determines the coil operating temperature. - ANSboiling temperature The boiling temperature and its relationship to the system exist in the ____. - ANSevaporator The clearance volume of a compressor cylinder is the ____. - ANSvolume of the space between the bottom of the valve plate and the top of the piston at the top of the stroke The condenser in a refrigeration system ____. - ANSdesuperheats the vapor from the compressor condenses the vapor from the compressor subcools the liquid refrigerant before it leaves the condenser The cross liquid charge bulb at the TXV contains fluid that ____.

• ANShas different characteristics from the system fluid The hermetic reciprocating compressor motor is essentially made of the same materials as an open type compressor motor. - ANSFalse The household refrigerator fresh-food compartment is a good example of ____ refrigeration. - ANSmedium- temperature The household refrigerator fresh-food compartment typically ranges from ____. - ANS28 to 40°F The primary function of an expansion device is to ____ - ANSlower the boiling point of the refrigerant far enough below the temperature of the load to get the needed heat transfer rate produce a reduction in the pressure on the liquid refrigerant regulate the flow of refrigerant into the evaporator The process

of removing heat from a place where it is not wanted and transferring that heat to a place where it makes little or no difference is known as ____. - ANSrefrigeration The purpose of a capillary tube is to ____. - ANSregulate the refrigerant flow into the evaporator lower the pressure of the liquid refrigerant lower the boiling point of the refrigerant The purpose of an externally equalized thermostatic expansion valve is to ____. - ANScompensate for excessive evaporator pressure drop The refrigerant in a condenser in a refrigeration system ____. - ANSrejects heat The rotary screw compressor uses an open motor instead of the hermetic design. - ANSTrue The screw compressor is used primarily in ____. - ANSlarge industrial refrigeration and air-conditioning systems The scroll compressor is one type of reciprocating compressor. - ANSFalse The shell of a hermetic type reciprocating compressor is generally considered to be on the low pressure side of the system. - ANSTrue The shell-and-tube condenser is cleaned ____. - ANSwith a brush after removing the end caps The temperature of the compressed gas leaving the compressor can best be described as ____. - ANSvery warm The TXV sensing bulb is mounted ____. - ANSon the suction line between the evaporator and the compressor What can be used to maintain the head pressure of a system with a water-cooled condenser?

• ANSwater regulating valve When the load on the evaporator

increases, the TXV ____. - ANSincreases the flow of refrigerant Which of the following can be used to maintain the head pressure of a system with an air-cooled condenser? - ANScondenser flooding valve fan cycling dampers or louvers