QMED Basic Refrigeration Practice Test

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• What is the primary function of a D-X Coil in refrigeration systems?
• What is a common cause of low refrigerant levels in a refrigeration system?
• What action can be taken to prevent flashing in the liquid line?
• What are the primary factors affecting refrigeration system efficiency?
• What is the primary purpose of a compressor crankcase heater?
• Which heat transfer mechanism involves the movement of fluids?
• What is a common characteristic of hydrofluorocarbons (HFCs)?
• What is one method of leak testing a refrigeration unit?
• What maintenance action can help prevent refrigerant leaks?
• What is the primary function of the condensing unit in a refrigeration cycle?
• What component allows an AC Heat Pump to reverse refrigerant flow for seasonal use?
• What is the primary purpose of a filter drier in a refrigeration system?
• What is the correct procedure for adding refrigerant to the low side of an AC system?
• Where in the refrigeration cycle can superheated vapor be found?
• What happens to the freezing point of water when salt is added?
• At which component does the refrigerant typically change its state?
• What is specific heat defined as?
• How does an oil return system contribute to the efficiency of a refrigeration unit?
• What issue leads to sweating of the compressor crankcase?
• What is the standard operating pressure range for R-134a in a domestic refrigerator?
• What might happen if a crankcase heater fails?
• What does the compressor do in a refrigeration system?
• What is one common method to check refrigerant levels in a system?
• When a substance changes state from a liquid to a gas, what happens to the spacing of its molecules?
• Why is it important for refrigerants to have a low boiling point?
• In what state does refrigerant typically enter the expansion valve?
• What maintenance action helps mitigate the adverse effects of compressor vibrations?
• What will cause the release of refrigerant from the oil/refrigerant mixture?
• What is the term for the frequent starting and stopping of a refrigeration system?
• What is the primary purpose of an oil return system in refrigeration units?
• Why is outside air regulated into the cooling coil of an AC system?
• What is the benefit of sub cooling the condenser in a refrigeration system?
• How does an expansion valve affect the refrigerant in a system?
• In a refrigeration system, where does the greatest drop in temperature occur?
• Which component is crucial to prevent refrigerant escape during maintenance?
• What is the primary concern when handling refrigerants?
• What is meant by the term liquid slugging?
• What does the acronym HFC stand for in refrigerants?
• How might vibrations impact refrigeration compressors?
• What does latent heat refer to?
• What is the importance of pressure-temperature charts for refrigerants?
• What is the term for the difference in pressure between the evaporator and condenser?
• What happens if the expansion valve is oversized?
• What is the primary function of the TXV in a refrigeration system?
• What is the purpose of a sight glass in refrigerant systems?
• What does a refrigerant do in a refrigeration cycle?
• What can cause a drop in cooling efficiency in a refrigeration system?
• Which component is crucial for regulating the flow of refrigerant in a system?
• Why is it important to ensure proper airflow over evaporator and condenser coils?
• What happens to refrigerant during hot gas defrosting?
• What impact does sub-cooling have on the efficiency of refrigerant?
• What is superheat in the context of refrigeration?
• What is the heat gained per pound of refrigerant in the evaporator called?
• What is the primary metering device used in a refrigeration system?
• What is the usual effect of too much moisture in a refrigeration system?
• Where is the latent heat of condensation removed from the refrigerant?
• What type of heat transfer occurs in the evaporator?
• Which method can be used to check for moisture in refrigerant?
• What is a common symptom of low refrigerant levels in a system?
• What problem can excessive circulation of lubricating oil with refrigerant lead to?
• What is the refrigeration cycle's first stage called?
• What causes the low-pressure cutout switch to actuate?
• What condition will most likely prevent the compressor from starting?
• What is the role of the compressor in a refrigeration system?
• When a compressor does not start, what should be checked first?
• What is a potential risk associated with a clogged condenser coil?
• What type of compressor is characterized by having zero gas pulsations?
• Which chemical in the upper stratosphere is an indicator of ozone layer depletion?
• What does the term "liquid slugging" refer to in a refrigeration system?
• What is the state of refrigerant entering the compressor of a refrigeration system?
• What is the state of refrigerant leaving the condenser in a refrigeration system?
• What does the performance of a refrigeration system largely depend on?
• In refrigeration systems, what does a "TXV" refer to?
• What components separate the high side from the low side in a refrigeration system?
• Which gas is commonly used in commercial refrigeration systems?
• The design of discharge pressure of a compressor primarily depends on what?
• Why is superheat important for a refrigeration system?
• What is the primary purpose of a refrigeration system?
• What components are universally included in all mechanical refrigeration systems?
• What kind of refrigerants are classified as CFCs?
• What is a potential result if certain refrigerants are combusted?
• What is the function of an electric defrost heater in refrigeration?
• What happens to the specific heat of water as it changes state?
• What is most likely to occur if the evaporator coil becomes covered with frost?
• What is the result of heat absorbed during a phase change?
• What function does the evaporator serve in low-temperature applications?
• What state does the refrigerant enter after passing through the evaporator?
• How is sensible heat observed?
• What is the role of lubricating oil in a compressor?
• What are common sources of moisture in a low pressure refrigeration system?
• What action should be taken if a unit is operating continuously?
• What is the significance of the saturation temperature of a refrigerant?
• In refrigeration, what is the primary purpose of the condenser?
• Why is it necessary to periodically check and clean condenser coils?
• Which type of compressor is commonly used as a booster compressor in a cascading refrigeration system?
• What occurs during the condensation process in a refrigeration system?
• Which method of heat transfer involves the direct transfer of thermal energy between materials in contact?
• What is the main indicator of a refrigerant leak in a system?
• Which action can lead to equipment failure in refrigeration systems?
• Which refrigerant is commonly used in domestic refrigerators?
• What is the color coding for the low-pressure gauge on a refrigeration gauge manifold?
• What happens during the condensation process in a refrigeration system?
• What state is the refrigerant in when it enters the metering device?
• What does the compressor's suction line do?
• What type of heat is the most important for refrigerant technicians?
• What could be a result of excessive cycling of a refrigeration compressor?
• What is a common method used for testing refrigerant leaks?
• What does it mean for a fluid to be classified as saturated?
• What is defined as the refrigeration system between the metering device and the compressor?
• Why is the proper disposal of old refrigerants important?
• What is the recommended practice for admitting fresh air to HVAC systems for optimal efficiency?
• What device is responsible for turning the compressor on and off?
• In a refrigeration cycle, what is the refrigerant primarily responsible for?
• Where does the refrigerant absorb the latent heat of vaporization?
• When does an automatic compressor start?
• Which component of the refrigeration cycle typically operates at a higher pressure?
• What is the primary purpose of the compressor in a refrigeration system?
• In which component does the refrigerant absorb heat?
• What causes frost to form on a compressor suction line?
• What can an oxygen indicator detect?
• Which type of heat causes a change in temperature?
• How do you calculate superheat?
• Adding salt to water impacts which point concerning phase change?
• In which state does one pound of refrigerant occupy the most space?
• What is the difference between a hermetic and a semi-hermetic compressor?
• What safety device is used to prevent excessive pressure in refrigeration systems?
• What occurs to the temperature of the refrigerant as it passes through the metering device?
• What does the ozone layer protect the Earth from?
• Which component in a refrigeration system is responsible for reducing the temperature of the refrigerant?
• What is a common effect of a refrigeration unit that is low on refrigerant?
• What are the four basic categories for the use of mechanical refrigeration?
• Why is regular maintenance crucial for refrigeration systems?
• What does the term "flooding" refer to in refrigeration terminology?
• What medium is commonly used as a coolant in water-cooled condensers?
• What could be a consequence of using the incorrect type of refrigerant?
• What type of heat is involved in melting and boiling?
• Why is monitoring high side pressure important in refrigeration systems?
• How frequently should compressor oil changes typically be performed?
• What is a consequence of oxidation of lube oil due to overheating?
• When starting a refrigerating compressor after a shutdown period, which valve should you manually throttle?
• Why is it important to manage discharge pressure in a refrigeration system?
• What does "venting" a refrigerant mean?
• What condition occurs when liquid reaches the suction line to the compressor?
• When should a refrigerant recovery machine be used?
• What can cause a refrigeration system to ice up?
• What does the term 'Tare Weight' refer to?
• How does improper refrigerant type affect the safety of a refrigeration system?
• How often should refrigerant pressures be checked in a working system?
• Which refrigerants are considered more environmentally friendly than CFCs?
• Which condition may occur if flooding happens in a refrigeration system?
• Which type of compressor is known to develop the most gas pulsations?
• What does total heat include?
• What will cause the suction line temperature to increase?
• As the temperature of any substance increases, how do the molecules behave?
• What does the pressure in the control tubing of a TXV depend upon?
• What would provide the best protection from large quantities of refrigerant leaking from a refrigeration unit in a semi-enclosed space?
• How can you determine if a refrigeration unit is low on refrigerant?
• What general frequency is recommended for checking refrigeration systems for optimal operation?
• What is described as the heat removed by the condenser from the refrigerant?
• Which type of compressor is widely used for household refrigeration systems?
• What is the role of a thermocouple in refrigeration systems?
• What happens to the refrigerant in the condenser?
• Why do we sub-cool the refrigerant prior to the TXV?
• What is one of the dangers of not monitoring high side pressure?
• What happens to the refrigerant in the compressor?
• What is the purpose of a compressor oil separator?
• What is a sign of a malfunctioning compressor?
• As 32°F liquid water is heated, what types of heat changes are observed?
• In refrigeration terminology, what is the state of the water we drink?
• What causes compressor crankcase oil to foam?
• What role does an evaporator play in a refrigeration cycle?
• What is the purpose of the upper piston rings in a compressor?
• What effect does moisture in the refrigerant have on a refrigeration system?
• Which component is responsible for regulating the flow of refrigerant in a refrigeration system?
• Which method of heat transfer relies on the movement of fluids?
• What does R-410A refrigerant primarily replace?
• What is a benefit of maintaining proper lubrication in refrigeration compressors?
• How do we lubricate reciprocating compressors?
• What is often used to bind the oil in a refrigeration system?
• What is the main function of the accumulator in a refrigeration system?
• What is the primary reason for installing sight glasses in a liquid line?
• Which of the following can cause high head pressure at the compressor?
• How is the refrigerant described when it leaves the metering device?
• What is a common indicator of a refrigerant leak?
• What does COP stand for in refrigeration?
• What can be the result of a blocked expansion valve?
• In what situation might you expect bubbles to appear in a sight glass?
• What will happen if excessive foam occurs in the compressor crankcase?
• What does the term "refrigerant leak detection" refer to?
• Which instrument is commonly used to measure refrigerant pressure?
• How does the evaporator affect the state of refrigerant?
• When a refrigeration system is short cycling, what does it indicate?
• What component is used to control the flow of refrigerant in a refrigeration system?
• What is the main purpose of dehumidifiers in an AC system?
• How does humidity affect a refrigeration system's performance?
• What type of refrigerant is R-12 categorized as?
• Why is it important to install expansion valves correctly?
• When assessing the efficiency of a refrigeration system, what should be monitored regularly?
• Which of the following is NOT considered a good thermal insulator?
• What effect does moisture have in a refrigeration system?
• How is a refrigeration ton defined?
• What effect does low refrigerant charge have on a refrigeration system?
• Which component operates by raising the pressure of refrigerant vapor?
• What is the main function of a compressor in a refrigeration system?