Basic Refrigeration and Charging Procedures Practice Test

These questions are part of the practice quiz. Start practicing

• Unless the system is undercharged, a sight glass will only what under higher loads?
• How do you verify dryness after evacuating the system?
• How does ambient temperature affect condenser pressure and charging decisions?
• Suction line accumulators are used on systems for added protection to ensure that all the refrigerant entering the compressor is what?
• What type of oil is typically used with R-134a and R-410A, and how does that differ from older systems?
• Which term describes vapor refrigerant heated above its saturation temperature?
• If you need the exact charging method for a fixed orifice system, which source should you consult?
• Which charging method is defined as introducing refrigerant as a vapor into the low side, used to avoid overfeeding the evaporator or when the system is off?
• What in the liquid line can be caused by any restrictive devices?
• For the precise charging method of a fixed orifice system, who should be consulted?
• Which statement best describes what the liquid line transports?
• During charging of a fixed orifice system, who must you consult for the exact method?
• What can be purchased and installed in existing systems to gain subcooling?
• In critically charged systems, the refrigerant charge is specified to which unit?
• For the exact charging method of a capillary orifice system, which source should you consult?
• Which action is recommended to avoid introducing air into the system during charging?
• What is the purpose of a filter-drier in a refrigeration system?
• What action should be taken instead of venting refrigerant to atmosphere?
• If you cannot reach the target superheat on a TXV system, what steps should you take?
• What is the role of the compressor in the refrigeration cycle?
• After charging, what symptom most strongly indicates non-condensables in the system?
• Which statement best describes R-134a, R-410A, and R-22?
• Subcooling reduces flash loss in the evaporator, allowing more of the liquid to vaporize for cooling. Which statement best describes this effect?
• When charging a capillary tube or fixed orifice system, who should you consult to obtain the exact charging method?
• What are the 3 conditions of a refrigerant
• Which of the following is a common metering device type used in basic refrigeration?
• Which statement best describes the purge guidance for a new cylinder?
• What is the proper range for compressor superheat in typical systems?
• Who provides the exact charging method for capillary systems, according to standard practice?
• To obtain the exact charging procedure for a capillary system, which entity should be consulted?
• Overcharging increases which type of subcooling, while head pressure elevates and higher compression ratios cause inefficiencies?
• Liquid/Suction line heat exchangers are often mounted in what line to transfer heat away from the liquid line and into the suction line?
• Why is proper refrigerant charge important for system efficiency?
• Why is moisture removal critical after a repair before recharging?
• What is subcooling and why is it important?
• Which charging method uses measuring condenser liquid-line temperature and condenser pressure to compute subcooling and adjust charge to reach the desired subcooling?
• Which statement correctly describes detecting air (non-condensables) in a system?
• Why are AXVs used in small equipment with constant evaporator loads?
• Under high load, what condition will the sight glass indicate if the refrigerant is not properly charged?
• Total subcooling extends from the 100% saturated liquid point to what?
• What ensures that no liquid refrigerant enters the compressor at low evaporator loadings when TXV valves lose control of superheat settings?
• Why should you not rely solely on a sight glass to determine charge?
• The only way to safeguard against liquid line flash gas is to what to the liquid before it experiences any pressure drops?
• What is the typical evaporator superheat target range used by many TXVs?
• Which of the following is a recommended check to verify a TXV is functioning properly?
• Which party is the definitive source for the exact charging method of capillary tube systems?
• What evaporator temperature range is recommended for air conditioning and heat pumps?
• Overcharging leads to elevated head pressure and higher compression ratios, causing what kind of inefficiencies?
• For confirmation of the exact charging method in a fixed orifice system, who is the primary reference?
• What does the receiver act like? What does the receiver do?
• What does the liquid line transport?
• Which condition is among common causes of high head pressure?
• Which leak-detection method uses UV dye tracing to locate leaks?
• How does a TXV regulate refrigerant flow?
• What are the two subcooling categories?
• Which is a typical AXV application in small equipment?
• Air conditioning charging requires monitoring of which two heat processes?
• TXV and AXV are examples of what kind of components in a refrigeration system?
• Where in a refrigeration system is an AXV located?
• Always charge what three components together under a high load?
• Why should you reference the manufacturer's service data when charging a system?
• What is referred to a liquid at temperatures below its saturation temperature for a given pressure?
• Which two components divide and separate pressures in an air conditioning system?
• Which component is subject to heat gains from product load and ambient that can vaporize liquid refrigerant?
• In air conditioning charging, which pair of temperature measurements are used along with air flow and compressor superheat?
• Which item is NOT typically part of a basic charging procedure?
• What are the three ways a capillary tube system can become blocked or restricted?
• What is superheat in refrigeration?
• Under what load should you operate refrigeration equipment when charging with refrigerants?
• Total superheat should be within what range to ensure adequate compressor cooling and preventive liquid control?
• What is the difference between recovery and recycling refrigerants?
• Non-condensables in the system typically cause which of the following?
• What is the first step in the complete charging procedure for a new installation?
• Which term describes the pressure-temperature relationship that exists only at the saturated state?
• What is the most accurate method to charge capillary and fixed orifice systems?
• Liquid subcooling affects system capacity and the effectiveness and capacity of which kind of metering devices?
• What two states do modern refrigerants exist in
• Why is venting refrigerant to atmosphere prohibited?
• Why must oils be matched to refrigerants, and what happens if they are not?
• Which leak-detection method uses a soap-bubble solution to reveal leaks?
• Which device is used on the suction line to ensure the refrigerant entering the compressor is liquid-free?
• Subcooling is defined as
• Which action is the final step in the complete charging sequence for a new installation?
• What is the function of the evaporator in a refrigeration system?
• Which term describes charging with a table or curve to determine superheat, rather than weighing the charge into the system?
• What is condensation?
• In larger commercial capillary tube systems, what is placed at evaporator outlets to catch liquid that may escape vaporization during startup?
• Which of the following is a typical cause of low suction pressure?
• How does a charging scale work in a basic procedure?
• Which component is NOT listed among the eight components of a standard refrigeration system?
• Capillary tube systems require an exact amount of refrigerant in the system. What term describes this?
• The first pass of the condenser does what to the discharge line gases?
• What is the function of the low-side service port on a manifold gauge set?
• Subcooling is best described as indicating which aspect of condenser performance?
• Latent heat
• Which option represents a common method to detect leaks in refrigeration systems?
• Name three critical checks to perform after charging a system.
• What tools are typically used for a basic charging procedure?
• After vacuum is established, refrigerant charge is added through which port on the gauge manifold?
• Which statement correctly defines condenser subcooling?
• What is condenser subcooling?
• What is a typical purpose of combining a TXV and AXV in refrigeration systems?
• When charging a capillary tube or fixed orifice system, whom should you consult to ensure you follow the exact method?
• What is the purpose of a purge and how is it performed for a new cylinder?
• An AXV's main function is to maintain a constant what in the evaporator under all loads, regardless of evaporator superheat?
• Which pair of pressures describes a symptom of a partially blocked capillary tube?
• Where does heat absorption occur in the refrigeration cycle?
• After achieving the desired vacuum and isolating the vacuum pump, the specified nameplate amount of refrigerant is added to which side of the system?
• Which charging method uses measuring suction line temperature and evaporator pressure to determine target superheat per the manufacturer and adjust the charge until the superheat matches?
• An improper refrigerant charge in capillary tube systems can cause compressor damage due to slugging and flooding. What term describes this issue?
• Balance Port TXV uses which mechanical feature?
• What common mistake should be avoided when using a sight glass on a charged system?
• How is subcooling measured?
• Which components house liquid and vapor refrigerant simultaneously?
• What is the purpose of the condenser?
• What is always referred to as a vapor?
• Line Pressure Amplification helps prevent what issue in the liquid line by overcoming line pressure losses?
• Heat gains from the product load and outside ambient travel through the sidewalls of what component to vaporize any liquid refrigerant?
• Where do you measure the compressor superheat?
• What is another important reason why condenser subcooling must be present?
• Which mixture decreases the capacity of TXV valves because capacity tables are based on vapor-free liquid at their inlets?
• Why should you purge a charging hose or cylinder before connecting to the system?
• Overcharging refrigerant will cause elevated which two pressures?
• Which instrument is used to measure vacuum at micron levels during dehydration?
• What is the next most efficient method to charge a capillary system after weighing into the system?
• A three-component system under high load consists of which trio?
• How is superheat measured?
• What is total subcooling?
• Which statement best describes the function of a TXV compared with a fixed-capillary system?
• Which condition describes refrigerant that is below its saturation temperature for the given pressure?
• Which charging method involves injecting refrigerant in liquid form through the liquid line while the system is running to achieve a precise charge and is typically used with fixed orifice or when a TXV requires?
• Why is subcooling an important process?
• Where should the thermistor be placed to measure the liquid line temperature near the expansion valve?
• What type of TXV has balanced pressures across the valve to negate variations in head pressure?
• A TXV controls what?
• Which of the following is a recommended check for TXV function?
• For the precise charging procedure of a fixed orifice metering device, whom should you consult?
• Where should the filter-drier be placed in the system?
• Which statement describes the role of condenser performance in diagnosing charging issues?
• Which parameter is factory-set to achieve a predetermined evaporator superheat, usually between 7 and 10 degrees Fahrenheit?
• Which are the three pressures acting on a valve?
• What is the role of a manifold gauge set in charging?
• Premature liquid flashing that reduces refrigeration effect occurs before entering which component?
• What is one key reason for using superheat in charging procedures?
• What is the effect of restrictive devices on the liquid line?
• When seeking the exact charging method for a capillary tube, which source provides the standard method?
• The compressor is also known as a what?
• Total superheat is also called what type of superheat, representing all the superheat on the low side?
• At what condition is there pressure/temperature relationships for refrigeration
• The valve will close due to increasing evaporator pressure, causing refrigerant flow to the evaporator to cease.
• Which TXV design senses evaporator pressure at the evaporator to compensate for friction pressure drops along its length?
• For the precise charging procedure, who is the authoritative source?
• Which of the following describes an advantage of the LPA system?
• When measuring the liquid line temperature at the entrance of the TXV or AXV metering devices, place the thermistor or thermocoupler on the liquid line about how many inches in front of the expansion valve and insulate it from ambient heat gains?
• What is the correct order of major components in the basic refrigeration cycle?
• Which component receives and stores the liquid refrigerant in the system, acting like a reservoir?
• What is a non-condensable and how does it affect system performance?
• Subcooling helps ensure what in a system?
• AXVs are found on small equipment with constant evaporator loads, such as
• What is the typical target vacuum level for dehydration?
• At higher loads, a sight glass in the liquid line will bubble if undercharged.
• If the refrigerant entering the TXV inlet is a liquid-vapor mixture rather than vapor-free liquid, what happens to the valve capacity?
• What are the risks of using the wrong lubricant for a refrigerant?
• How do you determine if a system has non-condensables after a charge?
• Which component is primarily responsible for metering refrigerant flow into evaporator?
• In a TXV, which pressure acts as the opening force on the valve?
• When verifying the exact charging method for capillary tube systems, who is the authoritative source?
• Liquid/Suction line heat exchangers are designed to transfer heat from the liquid line into which other path?
• What is the purpose of evacuating a system before charging?
• What minimum total superheat at the compressor is recommended to prevent liquid slugging at low load?
• Which two devices do not throttle open and close like TXV's and AXV's, making a receiver unnecessary to hold liquid from the condenser?
• When documenting charge information, which ambient condition detail is typically recorded?
• How does a fixed-orifice/capillary system regulate flow and what is a key drawback?
• Which statement best describes R-22?
• What is the main function of the condenser?
• What is the primary purpose of the filter-drier in the refrigerant circuit?
• Which component raises the pressure and temperature of the refrigerant vapor in the cycle?
• What is known as the 'LPA'?
• What is the function of the high-side service port on a manifold gauge set?
• Suggested evaporator superheat settings are what range?
• During the subcooling charging method, what two measurements are used to determine subcooling?
• What is the primary functional difference between a TXV and a capillary tube system?
• The evaporator temperature range specified applies to which equipment category?
• What happens in the expansion device?
• During startups in large capillary tube systems, vapors are drawn from the top of what component?
• When referencing the exact charging method for capillary tube systems, which party should be contacted?
• Why is it important to keep refrigerant cylinders upright during charging?
• The primary value of the LPA system is to ensure a solid column of liquid to which device, enabling the TXV to supply adequate liquid to which component?
• What is the purpose of the sight glass, and what does the presence of bubbles indicate?
• What is the function of the suction line?
• Capillary tube systems are critically charged because they lack which type of refrigerant control devices?
• During the superheat charging method, what two readings are used to determine the target superheat?
• The eight components of a refrigeration system.
• The superheat suppression process injects liquid refrigerant in the compressor discharge line or inlet of which component?
• How do you document charge information for future maintenance?