Basic Refrigeration Practice Exam

These questions are part of the practice quiz. Start practicing

• The compressor is where the refrigerant changes from a:
• Which leak-detection method is simple and visual for larger leaks?
• Which term describes the practice of processing used refrigerant to meet new product specifications?
• The condenser:
• A subcooling reading that is too high requires:
• Evaporator starvation is indicated by which condition?
• What does a milky appearance in vacuum pump oil indicate?
• What personal protective equipment (PPE) is typically required when handling refrigerants and charging systems?
• What is the purpose of a sight glass with a moisture indicator in some refrigeration systems?
• Which statement best describes saturation in refrigeration and how it relates to pressure?
• What instrument is used to measure a deep vacuum?
• The pressure in a refrigeration system is changed in the _____.
• Which component is primarily responsible for circulating refrigerant through the system?
• What is an accumulator and when is it used in a refrigeration system?
• How does humidity affect refrigeration load and coil performance?
• Blended refrigerants must be charged as a:
• In a refrigeration cycle, which device's primary purpose is to maintain superheat?
• What are the main compressor types used in basic refrigeration and a brief benefit of each?
• Where does superheating occur?
• What is the purpose of a capillary tube in some DX evaporators?
• Which term defines the condition where a liquid and its vapor are in equilibrium at a specific pressure?
• In a typical startup sequence for a packaged DX unit, which step is performed first after power and safety checks?
• What is the function of a metering device's target superheat?
• What controls the pump-down solenoid valve?
• A mullion heater is installed around which part of a large cooler?
• Which statement best describes the EPR valve's role in the evaporator system?
• R-404a is classified as a
• Define coefficient of performance (COP) in a refrigeration system and how it relates to efficiency.
• Why should air be purged from refrigerant lines during servicing?
• The compressor in a refrigeration system ____.
• Type I EPA Refrigerant Certification covers:
• Why is it important to follow refrigerant recovery procedures during service?
• Which statement about ozone depletion potential (ODP) and global warming potential (GWP) is true?
• Where does subcooling occur?
• Which device is used to reduce pressure before it enters the evaporator?
• In which component does the refrigerant change from vapor to liquid?
• What is the function of an EPR valve?
• Which of the following is a valid leak-detection method that provides fast and sensitive readings?
• R-134a is classified as a
• What is a common consequence of slugging in a reciprocating compressor?
• How can improper refrigerant charge affect electrical currents in the system?
• Which refrigerant is typically used in coolers?
• In a TXV-based direct expansion system, charging is adjusted to achieve the specified evaporator superheat. What are the primary measurements used to determine superheat and verify TXV operation?
• How do you check for proper oil return to the compressor?
• A frying pan on a stove is an example of which heat transfer?
• What is the function of a CPR valve?
• Which refrigerant group is thought to be the most damaging to the ozone layer?
• What is liquid slugging and how can it be prevented?
• Which statement about condenser type is NOT accurate?
• In a TXV, what is the primary control variable?
• What considerations are there when piping refrigerant lines for insulation and vibration?
• What is the effect of air entrainment in the refrigerant system?
• The type of heat that brings about a change in temperature but not a change in state is:
• Compare capillary tube and thermostatic expansion valve (TXV) as metering devices in DX systems.
• What is the function of an oil separator in a refrigeration system?
• When charging a TXV-equipped refrigerant system, what is the recommended method?
• What is oil return and how do you ensure it is adequate?
• If a vacuum has been pulled on a system and there is a leak, the vacuum gauge will:
• The condenser is where refrigerant changes state from a:
• Which statement best describes the relationship between head pressure and condenser capacity/COP?
• Which observation most directly indicates a dirty evaporator coil when diagnosing performance?
• How does the pressure-enthalpy (P-H) relationship help diagnose refrigerant charge and state in a system?
• Which refrigerant is classified as a zeotrope in the given list?
• What safety devices protect a refrigerant system from abnormal pressures, and where are they typically located?
• Which option describes proper documentation for refrigerant recovery?
• What is a P-H diagram used for in service practice?
• Which of the following correctly defines tare weight in cylinder handling?
• Differentiate dry bulb and wet bulb temperatures and explain how humidity affects cooling load calculations.
• When charging a TXV-controlled refrigeration system, how should you determine the correct refrigerant charge?
• From a maintenance perspective, identify the major differences between a scroll compressor and a reciprocating compressor.
• What is superheat in a refrigerant system?
• How should you interpret a suction pressure reading when diagnosing a cold room that isn't cooling?
• Which statement about safety devices in refrigeration systems is accurate?
• Which condition is most associated with an evaporator that is flooded?
• In a thermostatic expansion valve, which provides the opening force?
• When is the best time to take a superheat reading?
• What is the purpose of the crankcase heater on some compressors?
• What is the purpose of MSDS guidelines when handling refrigerants during charging?
• Which measurements are used to verify proper refrigerant charge in addition to pressures?
• In a direct expansion evaporator, where does the refrigerant begin to evaporate?
• Blended refrigerants separate at different rates because of different
• What happens if a TXV fails to sense evaporator load?
• What is the purpose of a hot gas by-pass valve in some systems?
• Which units are used to express refrigerant charge quantities in service and why?
• Liquid refrigerant is charged into the ________ when the system is in a vacuum
• Which refrigerant is typically used in freezers?
• Which corrective action is appropriate for a dirty condenser affecting cooling capacity?
• Which option correctly lists common refrigerants and a major environmental consideration for each?
• What is subcooling and why is it important for system performance?
• Why is it important to distinguish non-condensables from refrigerant during startup checks?
• Which device helps separate oil from refrigerant and returns oil to the compressor?
• Which statement best describes subcooling measurement?
• How does a thermal expansion valve (TXV) sense evaporator load?
• What is superheat in a basic refrigeration system?
• Which of the following is a visual sign of a refrigerant leak?
• How is refrigeration capacity expressed and what does one ton represent?
• When charging a refrigeration system, the high side should be charged only when the system is in which condition?
• Explain the difference between direct expansion (DX) and flooded evaporator configurations.
• Why is it important to maintain proper service valves and capillary stops?
• Explain the difference between a 'free cooling' mode and standard cooling.
• Name three common faults that cause reduced cooling capacity and how to verify them.
• R-500 is classified as a
• Explain why energy efficiency class measures like EER or COP are used and what they indicate.
• Which statement best describes the role of a metering device in a refrigeration system?
• Which component is the location where the refrigerant changes state from a liquid to a vapor?
• Which component is designed to prevent off-cycle migration of refrigerant?
• In a basic vapor-compression cycle, what is the state of the refrigerant when it leaves the evaporator?
• In a dirty condenser coil scenario, what effect does it have on system performance?
• What gas should never be used to pressure test for leaks?
• Which of the following is a description of a mullion heater?
• What does a moisture indicator color change in a sight glass signal?
• The metering device is where the refrigerant changes from a:
• Which refrigerants are commonly used today and what environmental considerations apply?
• Which indicator is commonly used to assess lubrication status in a compressor when equipped?
• Which statement correctly describes the flammability classification of R-32 compared with R-410A?
• Which compressor type is generally easier to service?
• What is the primary function of the metering device?
• What statement best describes the basic refrigeration cycle?
• The metering device is where the refrigerant changes from a high pressure liquid to a low pressure liquid.
• What effect does improper airflow across the evaporator have on refrigeration performance?
• Explain the significance of leak testing and common methods used.
• How is condenser subcooling identified, and why is it important?
• Explain the difference between direct expansion (DX) and flooded evaporator systems.
• What is air purge or air removal in water-cooled condensers and why is it needed?
• What does COP stand for and how can it be improved in a basic system?
• What roles do the condenser and evaporator play in heat transfer within a refrigeration system?
• In a basic system, how does subcooling affect metering and performance?
• What is the function of an accumulator?
• What is a hot gas defrost and when is it used?
• What is a low ambient control and why is it used?
• Name three non-technical practices that help refrigeration technicians maintain safety and efficiency.
• Recovery tanks should only be filled to _____ capacity.
• What information can be read from a pressure-enthalpy diagram?
• Name a sign of an overfed evaporator that can cause liquid slugging in the compressor.
• Which leak-detection method is especially effective for halogenated refrigerants?
• Which of the following is a typical indicator of a flooded evaporator?
• Which device prevents off-cycle migration?
• What role do fans and airflow play in refrigeration system performance?
• Why is an externally equalized valve needed?
• R-22 can be charged as a vapor through which part of the system's low side?
• What is the purpose of a suction accumulator or oil separator in a system?
• Explain the concept of dew point and why condensation may occur on refrigerant lines.
• To reprocess refrigerant to meet new product specifications is called:
• A mullion heater is described as:
• Which statement about the relationship between pressure and saturation temperature is true?
• If the evaporator superheat is too low, what is a potential risk?
• How do ozone depletion potential (ODP) and global warming potential (GWP) differ in refrigerants?
• One ton of refrigeration is equal to how many BTU per hour?
• Which component prevents off-cycle migration?
• What type of evaporator needs an external equalizer valve?
• Type I certification applies to which category of appliances?
• Which of the following describes the dew point concept as it relates to condensation on lines?
• Which component handles the change from low pressure vapor to high pressure vapor?
• What keeps water from condensing in the 2nd stage of a vacuum pump?
• One ton of refrigeration is equal to how many BTU per hour?
• Where is a high-pressure switch typically located in a refrigerant system?
• What is the role of glycol or brine solutions in water-cooled refrigeration systems?
• During hot pull down, which valve is designed to prevent compressor overload?
• Why is removing moisture with a vacuum pump important during service, and what level is considered a good vacuum for most systems?
• Name three common condenser types used in refrigeration systems and a key characteristic of each.
• Define the function of a low-pressure control in a refrigeration system.
• What is the difference between a thermostatic expansion valve (TXV) and an adjustable orifice?
• What is the purpose of a sight glass with a moisture color indicator and how to interpret it?
• How does an electronic expansion valve (EEV) differ from a TXV?
• R-22 is classified as a:
• What is a practical method to prevent evaporator coil frost and ice buildup in a refrigerated case?
• Explain the purpose of a reheater in some multi-stage systems and when it is used?
• What is the typical function of a receiver-drier in a refrigeration system?
• Discuss the importance of electrical metering and control wiring in refrigeration systems.
• Which valve is automatically controlled and opened/closed by an electromagnet to regulate a fluid passage with a movable core?
• Which reading is most associated with evaporator underfeeding when diagnosing performance?
• What condition is addressed by ensuring an adequate oil return path to the compressor?
• What is a common disadvantage of using a fixed-capillary metering device in direct expansion (DX) systems?
• In a phase-change process within the evaporator, heat added to the refrigerant results in:
• Which refrigerant characteristic is emphasized for environmental regulations?
• How would you safely recover refrigerant from a system?
• What is the practical purpose of subcooling in the condenser output?
• How would you determine if an evaporator coil is dirty and causing poor performance?
• The empty weight of a refrigerant recovery cylinder is known as the _____ weight.
• Besides crankcase pressure, what other pressure does the oil safety control monitor?
• What is the purpose of defrost cycling in evaporator systems?
• R-22 can be charged as a _____ through the low side of the system.
• Compare R-410A and R-32 in terms of pressure, compatibility, and flammability considerations.
• What refrigerant group is thought to be the most damaging to the ozone layer?
• Which condition is most likely to increase head pressure in a condenser system?
• What is the primary risk if liquid slugging occurs during startup due to unprevented refrigerant migration?
• Which statement best contrasts an adjustable TXV with a fixed-capillary metering device?
• Which device is described as automatically controlled and actuated by an electromagnet to regulate flow?
• What type of heat causes a change in temperature without a phase change?
• Which device's operation is most closely tied to controlling superheat?
• Why is pressure drop across the evaporator and condenser important to consider in system design?
• When a freeze-up occurs at the evaporator coil, what is the proper troubleshooting sequence?
• Why is a filter-drier installed in refrigeration systems?
• Which device is described as keeping pressure up in the evaporator?
• Subcooling is best described as:
• What is a compressor’s crankcase and why is crankcase pressure important?
• What is the role of the evaporator and condenser in heat transfer within the cycle?
• Which statement best captures the importance of electrical metering and control wiring in refrigeration systems?
• What do head pressure and suction pressure refer to in a refrigeration system, and why are they important for performance?
• Name at least three safety devices used on basic refrigeration systems and describe their purpose.
• According to the fundamental law of thermodynamics, heat always moves from
• What problem do non-condensable gases cause in a condenser, and how can it be addressed?
• A superheat reading that is too high requires:
• What is the effect of ambient temperature on refrigerant charge and system performance?
• Externally equalized valves are used to address which issue in evaporators?
• Where is a low-pressure switch typically located in a refrigerant system?
• Why is oil choice and oil return important in reciprocating compressors?
• Moisture reacts with refrigerants to form:
• The evaporator in a refrigeration system ____.
• In a low ambient control strategy, what equipment might be used to manage head pressure?
• What symptom is commonly associated with refrigerant undercharge?
• Which set correctly identifies the four major components of a basic vapor-compression refrigeration cycle?
• What two pressures does an oil safety control monitor?
• Which action should occur immediately after confirming safety interlocks in startup?
• Which unit of measurement is commonly associated with measuring deep vacuum using a micron gauge?
• Which refrigerant is commonly used in commercial freezers?
• What is the effect of a malfunctioning expansion device on evaporator operation?
• The type of heat that brings about a change in state but not a change in temperature is:
• The refrigerant in a refrigeration system changes state in the _____.
• What is the process called for removing refrigerant from a system?
• How does a pressure-temperature (P-T) relationship help in diagnosing a charged refrigeration system?
• What is the purpose of a service valve with a Schrader core?
• Vacuum pump oil contaminated with water will appear _____ in the sight glass.
• Subcooling helps ensure proper metering and prevents which issue?
• Which statement about condenser type on system operation is true?
• Which of the following indicates a defrost method is inadequate in an ice-building system?
• In a vacuum system, where is liquid refrigerant charged during recovery?
• What is the function of a receiver in a refrigeration system?
• What is the role of the condenser in heat rejection and how does condenser type affect system operation?
• Blended refrigerants separate due to differences in their
• Explain why an evacuated system is necessary before charging and what could happen if moisture remains.
• What is a common cause of high head pressure in condenser systems?
• Which safety practices should be observed when servicing refrigeration equipment?
• What is the primary function of a high-pressure switch in a refrigeration system?
• How is evaporator superheat defined and calculated?
• Define subcooling degree and how it is measured.
• Which component prevents water condensation in the second stage of a vacuum pump?
• In a water-cooled condenser, what is typically used as the coolant?
• What is a likely consequence of refrigerant overcharging a system?
• Why is refrigerant oil compatibility important in lubrication of compressors?