ESCO Refrigeration Practice Test

These questions are part of the practice quiz. Start practicing

• A mechanical shaft seal is necessary on a...
• Subcooling is defined as which of the following?
• An air conditioning system that is oversized can cause...
• A decrease in superheat causes the TXV to begin to
• List common reasons for a system to display low refrigerant charge and how to verify each.
• In testing the efficiency of an air-cooled condenser, the refrigerant condensing temperature should be no more than approximately how many degrees higher than the leaving air temperature?
• A TXV is designed to maintain...
• Why is unobstructed condenser airflow crucial?
• What is the purpose of the metering device in a vapor-compression refrigeration cycle?
• When a TEV or a capillary tube is used as a metering device, a low refrigerant charge will cause...
• Which maintenance step helps prevent compressor overload in hot weather conditions?
• Which statement best describes the reason for slight suction-line superheat in a refrigeration system?
• The main function of the condenser in a refrigeration system is to remove heat from the refrigerant.
• Which of the following is not a symptom of a hermetic system that is low on refrigerant?
• In the evaporator, the refrigerant absorbs latent heat from the space which causes it to
• A compound pressure gauge measures
• The heat removed from the refrigerant by the condenser is which type of heat?
• In a vacuum of 28 inches of mercury, at what temperature will water begin to vaporize?
• Which condition would you expect from an overcharged refrigerant in a capillary tube system?
• Which statement about slight suction-line superheat is true?
• A decrease in superheat causes the TXV to begin to
• Using a manifold gauge set, high-pressure readings primarily indicate which system area?
• Which loads should the evaporator coil design primarily address?
• Which practice helps ensure the correct oil type is used after service?
• If the cut off plate is removed from a blower assembly, how would this effect blower performance?
• Which of the following is a common cause of compressor short cycling and how would you diagnose it?
• In a direct expansion evaporator system, the refrigerant entering the evaporator is best described as
• An overcharge of refrigerant will cause which condition?
• A faulty condenser fan motor on an air conditioning system will cause these symptoms...
• Which gauge is used to measure vacuum at the micron level in HVAC systems?
• Which of the following statements best describes the evaporator airflow requirement for residential AC?
• What is the primary purpose of a service valve in a refrigeration system?
• What is a typical purpose of a liquid-to-suction heat exchanger in refrigeration systems?
• A low refrigerant charge in a system using both TEV and capillary tube will cause which pressure change?
• Compared to R22 systems, the flow rate of a thermostatic expansion valve (TEV) in a 410A system is approximately what?
• Refrigerant R-134a vapor enters the condenser at 124 psig, 100°F and leaves at 80°F. Its pressure will be approximately...
• Which refrigerant is HCFC and commonly used in older residential HVAC systems?
• Before opening a vapor compression system for service, what must be done with the refrigerant?
• What is the role of an accumulator in the oil return path?
• While troubleshooting a residential split system, the service technician finds low operating pressures and low system amperage draw. This could be an indication of:
• Which of the following types of air conditioning compressors is most energy efficient?
• Heat added to a vapor after the change of state is called?
• In an air conditioning system that uses a TXV, the evaporator outlet temperature is usually
• The AXV is designed to maintain...
• Distinguish between refrigerant reclaim, recycling, and recap, and describe when each is required.
• After installing a new system, describe a standard charging procedure using the superheat method and what data to record.
• Which statement defines the dew point temperature?
• Which of the following describes proper PPE and lockout/tagout practices when servicing refrigeration equipment?
• Which safety attribute is a key reason for keeping refrigerant cylinders upright and away from heat?
• A rise in evaporator pressure causes the AXV to begin to
• Why is proper documentation of service data and test results important in refrigeration work?
• Which electrical checks help prevent compressor overload?
• In a DX evaporator system, the refrigerant enters the evaporator as
• A low pressure cut-off switch is used to...
• What pressure is sensed by the TXV's sensing bulb?
• An increase in head pressure causes ___ refrigerant to flow through a capillary tube.
• When using an electronic leak detector, at what rate should the sensor probe be moved to survey for leaks?
• Fan airflow pressures are usually measured in...
• What is the primary purpose of an accumulator?
• When connecting copper to steel, the recommended brazing filler alloy is a...
• Which sequence correctly describes how to calculate evaporator outlet superheat?
• When charging a system, how do you decide whether to use the superheat method or the subcooling method?
• Which type of expansion valve is described as solid-state and controlled by an NTC parameter?
• Provide approximate normal high-side and low-side pressure ranges for R-410A at typical outdoor temperatures.
• Which oils are commonly used in refrigerant systems, and what steps help prevent cross-contamination when replacing oil?
• The clearance space in a reciprocating compressor
• Where should the liquid line filter dryer be installed in a typical DX system?
• What is the purpose of a micron gauge in vacuum testing of refrigeration systems?
• An overcharge of refrigerant will cause:
• A refrigerant overcharge in a capillary tube air conditioning system will cause these symptoms...
• Capillary tube metering devices are described as which type of restriction?
• When diagnosing a compressor that won't start, which step best aligns with a proper starting-issue checklist?
• Zero psia is:
• Which is not a thermodynamic property of refrigerants?
• Capillary tube metering devices are best described as
• What are safe practices for handling refrigerant cylinders, including weight checks and storage?
• What is the generally accepted range for evaporator air flow in cfms per ton of residential air conditioning?
• How is subcooling measured, and what does it indicate about system performance?
• In the energy balance example, the heat gained by the water equals the heat lost by the refrigerant.
• Frost on the suction line indicates:
• Which condition indicates the presence of frost on the suction line?
• Which statement best describes the regulatory guidance for reclaim, recycling, and recap of refrigerants?
• Which statement is not true of a capillary tube metering device?
• Which symptom would indicate an oil-logged condenser?
• A TXV has three operating pressures...
• Which fault is most likely to cause high suction pressure and high discharge pressure in an air conditioning system?
• How can you tell if a system uses R-410A versus R-22 from labeling and service data, and why does it matter for pressures?
• What is the state of refrigerant entering the condenser?
• Zero psig is the same as which condition?
• At a residential service call with no cooling and unit completely out of refrigerant, the technician decides to use a trace amount of refrigerant and ___ in order to pressurize the system
• A restriction in the metering device can cause which evaporator condition?
• The temperature rise method of determining air volume is applicable to which equipment?
• A liquid to suction heat exchanger is often used to...
• Why is a vacuum applied to the isolated section before re-pressurizing after service?
• For an R410A system with a gauge reading of 124 psig and a suction line temperature of 54°F, what is the operating superheat?
• Liquid line sweating near the dryer is most likely caused by:
• In an air conditioning system that uses a thermostatic expansion valve, the temperature of the evaporator outlet will usually be...
• Electric defrost and hot-gas defrost cycles operate and what are practical differences?
• How does UV dye leak detection work and what color indicates a leak under UV light?
• Bubbles in the sight glass could indicate which condition in a system using a thermostatic expansion valve?
• After observing a liquid line leak repair and system recharge, a noisy, hot compressor likely indicates which problem?
• A low refrigerant charge in an air conditioning system will cause these symptoms...
• Which statement is not true about capillary tube metering devices?
• A TEV bulb which becomes detached from the suction line will cause these symptoms...
• Which component has no moving parts and is commonly used as a fixed restriction in metering?
• An inefficient compressor is usually indicated by ___ head pressure and ___ suction pressure.
• Which condition is typically observed when a TEV bulb becomes detached from the suction line?
• Which method can be used for leak detection with all high-pressure refrigerants?
• What role does cylinder fill percentage play in refrigerant handling and what safety precautions should be followed?
• Why is refrigerant-oil compatibility important and what steps should you take when replacing oil?
• ___ can be used for leak detection with ALL high pressure refrigerants.
• Which statement is not true about a capillary tube metering device?
• Why is an inline filter-drier used and where is it placed in the system?
• A compressor that has a broken Reed valve will cause these symptoms...
• What is refrigerant recovery efficiency and why is it important for compliance?
• Three basic types of condensers are water cooled, air cooled, and ___ cooled.
• In the evaporator, latent heat transfer occurs as the refrigerant boils and absorbs heat
• The evaporator's function is to:
• Which OSHA electrical-safety standards apply to HVAC technicians working on energized equipment?
• Air or other noncondensable gases in a capillary tube air conditioning system will cause these symptoms.
• What type of gauge is used to measure microns?
• Which statement correctly describes the evaporator pressure regulating valve (EPR)?
• Which of the following cannot be used as a low ambient temperature control?
• What are common methods for leak testing refrigerant circuits and what precautions should you take?
• What maintenance consideration is particularly important for microchannel coils?
• Which option is NOT a TXV operating pressure?
• During condensation, the refrigerant releases heat to the surroundings.
• What does the sensing bulb of a TXV/EVV do and where should it be placed?
• In testing the efficiency of a water-cooled condenser, the refrigerant condensing temperature should be no more than approximately how many degrees higher than the leaving water temperature?
• What is the function of the condenser in a vapor-compression refrigeration system?
• Which methods remove moisture from a refrigeration system?
• Which statement best describes a thermostatic expansion valve and a capillary tube in terms of control, efficiency, and operating range?
• The first function the condenser must perform is to ___ the refrigerant before condensing can occur.
• An inefficient compressor is usually indicated by which combination of head and suction pressures?
• The AXV best suited for operation under which condition?
• What is oil return and how do suction-side components help ensure it?
• Back seating a two-way service valve results in which condition?
• How is superheat defined?
• In the evaporator, latent heat is transferred from the refrigerated space to the refrigerant.
• What is the typical target superheat for common residential systems?
• In a basic vapor-compression refrigeration cycle, which component is responsible for raising the pressure and temperature of the refrigerant vapor?
• A system with a leak in the liquid line was repaired, evacuated, and recharged. When started, the compressor is noisy and running hot. The most probable cause is...
• What steps should you take to verify system cleanliness after brazing or major repairs?
• In which applications is R-404A typically used?
• What is the recommended evacuation procedure to remove moisture from a system?
• A OF a TEV bulb that has detached from the suction line will typically produce which pressure condition?
• Which of the following accurately describes EPA requirements for refrigerant recovery?
• A refrigerant gives up heat when:
• Which vacuum level is typically targeted when evacuating a system to remove moisture?
• A residential split system had a compressor replaced last week; now the unit is not cooling properly. The evaporator seems starved of refrigerant. The liquid line is sweating where it leaves the dryer. This is most likely the result of:
• To remove as much moisture as possible from a system, what evacuation procedure is recommended?
• If excess refrigerant is charged into a system, the result is typically
• When topping off an operating system containing a blended refrigerant, how should the refrigerant be introduced?
• How is superheat adjusted on many metering devices?
• Which statement about capillary tubes is true?
• A thermal-electric (solid state) expansion valve is controlled by
• Which factor does a TXV primarily respond to in regulating refrigerant flow?
• Which component is primarily part of the high-side circuit in a typical refrigeration system?
• What is the function of the evaporator in a vapor-compression refrigeration system?
• Which statement best contrasts electric defrost and hot-gas defrost in terms of heat source and typical use?
• Which condition is commonly associated with a low refrigerant charge in the system?
• How should you prevent refrigerant oil from contaminating the suction line and what precautions apply when opening or brazing?
• Which of the following is a typical sign of a malfunctioning TXV/EEV?
• If the line temperature is 70°F and the pressure corresponds to a saturated suction temperature of 42°F, what is the system's superheat?
• Why is purging lines with dry nitrogen during brazing important?
• Water enters a condenser at 80°F and leaves at 100°F; what is the water temperature rise?
• What is the purpose of the receiver in a vapor-compression refrigeration system?
• Differentiating evaporator and condenser coils, where heat transfer occurs and what state changes take place?
• The main function of the condenser is
• A low refrigerant charge in a system with an AXV metering device will result in which condition?
• In the condenser example, the BTU transferred by the water is
• A centrifugal compressor is typically associated with which of the following characteristics?
• What is a potential consequence of moisture in a refrigeration system?
• How can you tell if the condensate drain is blocked and what steps fix it?
• Solid contaminants such as sludge and carbon, from a severe hermetic compressor motor burnout are best removed...
• Before servicing a system, what equipment is required to handle refrigerant safely?
• What is a typical result of an incorrect refrigerant charge?
• Which action best removes solid contaminants after a severe hermetic compressor burnout?
• What is the function of a receiver in a refrigeration system, and when is a receiver used?
• Why is nitrogen or dry purge used during brazing of refrigerant piping?
• What is the typical state of refrigerant in the suction line?
• What is the purpose of a crankcase heater and when should it be energized?
• Which term describes heat transfer during vaporization?
• What is the minimum vertical drop from the outlet of the condensate drain pan to the inlet of the P trap?
• Why should nitrogen be used to pressurize or purge a system prior to leak testing and brazing?
• Compare R-407C and R-404A in terms of typical applications and operating temperatures.
• In a pump-down system, where is the solenoid valve located?
• Before leak testing, what is a critical safety/environmental precaution you should take?
• Which indicators signal moisture in a refrigeration system and how can moisture compromise performance?
• Which of the following best describes the typical relationship between evaporator outlet and inlet temperatures in a TXV system?
• An accumulator is used to
• What is the purpose of a liquid-line filter-drier and where should it be installed?
• What is a microchannel coil and what are its advantages and maintenance considerations?
• The temperature at which moisture will start to condense from the air is called
• The temperature rise method of determining air volume can be used on:
• When an AXV is used as a metering device, a low refrigerant charge will cause...
• A partially iced over evaporator can be caused by...
• Which device is used to prevent evaporator pressure from falling below a set limit?
• In a water-cooled condenser scenario, 10 lbs of refrigerant loses 20 BTU per lb, and 10 lbs of water passes through with the entering water at 80°F. What is the water leaving temperature?
• Which statement correctly describes high-side and low-side pressures and subcooling?
• What is the function of a metering device in a refrigeration system?
• Which statement about capillary tubes is true?
• Between which components is the liquid line filter dryer installed?
• How does humidity affect evaporator frosting and energy efficiency?
• A partially clogged capillary tube can cause which evaporator condition?
• Which parameter does the oil pressure safety switch monitor?
• A customer complains their air conditioning system runs constantly but does not cool well, the suction line is very cold and the compressor is sweating. The most likely cause is:
• Which statement best describes compressor types and their typical characteristics?
• Why is adequate airflow across the evaporator essential, and what are common causes of restricted airflow?
• What is the function of a low-pressure switch in a compressor-controlled system and what fault conditions could trigger it?
• A dirty evaporator in an air conditioning system will cause these symptoms...
• Removing the cut off plate from a blower assembly would most directly affect which parameter?
• The oil pressure safety switch is operated by...
• Where would a sight glass normally be located in a refrigerant system?
• Which statement best describes the condenser inlet state?
• Which statement describes the function of an oil separator in a refrigeration system?
• A liquid receiver is used to
• In an R134a system, the high pressure gauge reads 143 psig and the liquid line temperature at the condensing unit is 95°F. What is the operating system superheat?
• In an air conditioning system that uses a TXV, the evaporator outlet temperature relative to the inlet is usually
• The purpose of an evaporator pressure regulating valve (EPR) is to...
• When mounting a TXV sensor bulb, which of the following is NOT true
• A decrease in superheat causes the TXV to
• What is the maximum operating pressure setting for an acetylene torch?