Mechanical for A/C Practice Test

These questions are part of the practice quiz. Start practicing

• If a system will not hold a vacuum after evacuation, what does this indicate?
• If energy is added to a substance, then ____.
• Which refrigerant has a zero Ozone Depletion Potential (ODP), low Global Warming Potential (GWP), and is highly flammable?
• Leak testing a low pressure refrigeration system with nitrogen in excess of 10 psig could cause which component to fail?
• What is the environmental impact of refrigerant leaks?
• Small pressure above or below atmospheric pressure is primarily measured in ____.
• Where should recovery start with an air-cooled condenser on the roof and the evaporator on the first floor?
• The abbreviation for refrigerants containing chlorine, fluorine, carbon, and hydrogen is ____.
• You can save time recovering the refrigerant from a system by removing as much as possible in the ___________________ phase?
• Ice melts in iceboxes because ______.
• What is the requirement for the recovery process of small appliances?
• The abbreviation for refrigerants containing fluorine, carbon, and hydrogen is ____.
• What is the safest way to handle used refrigerant when transporting it?
• Which component is essential for the recovery of refrigerant during maintenance?
• When refrigerant enters the compressor, what is its state?
• When must recovery equipment used for appliances be certified by an EPA approved laboratory?
• What is an indicator of a leak in a high-pressure system?
• The ______ are used to change the vapor to a liquid and the liquid form back into a vapor in the refrigeration cycle.
• To determine a system's subcooling value, from which temperature should the liquid line temperature be subtracted?
• When are appliances not required to be evacuated to the prescribed level?
• The compressor in a refrigeration system ______.
• What is the maximum allowable leak rate for appliances containing more than 50 pounds of refrigerant?
• Which of the following is NOT a requirement for refrigerant handling?
• When checking for non-condensables inside a recovery cylinder, why should the technician allow the temperature of the cylinder to stabilize to room temperature before taking a pressure reading?
• What is a significant feature of zeotropic blends compared to azeotropic blends?
• The process of pumping a system's entire refrigerant charge into the liquid receiver is called what?
• If the pressure of a gas remains constant, which law indicates that its volume varies directly with absolute temperature?
• The refrigerant R-134a is classified primarily as which type of refrigerant?
• When charging a system with refrigerant, the technician should put the low- and high-side service valves in which position?
• What describes the nature of an azeotrope in refrigerants?
• How does using a vacuum pump improve the maintenance of HVACR systems?
• What type of systems are technicians certified to recover refrigerant from after passing the small appliance examination?
• During vapor removal from a low-pressure refrigeration system, which should be true about the system operations?
• What does ozone in the stratosphere consist of?
• Two-part epoxy resin kits usually include one tube filled with epoxy and another tube filled with what?
• What is the maximum allowable factory charge of refrigerant for Type 1 appliances?
• What is the primary function of an expansion valve in a refrigerant system?
• If EPA regulations change after certification, what is the technician's responsibility?
• Many recovery cylinders use a safety device to turn off the recovery machine when the cylinder is 80% full. What is this device?
• As a substance is heated, its ____ tends to increase.
• Refrigerants in large quantities can cause suffocation because?
• What type of heat is primarily involved in the evaporation process of refrigerants?
• How much refrigerant must a recovery device be capable of recovering if the compressor is operating?
• What produces a cooling effect when refrigerant enters an evaporator?
• Active recovery utilizes what system component to pump refrigerant into a recovery cylinder?
• What is the cylinder color code for R-134a?
• Which of the following refrigerants is considered ozone-depleting?
• Evaporative cooling systems rely on the cooling effect derived from a ____.
• In a closed circuit, if the volume decreases, what happens to the pressure of a gas?
• Which of the following repairs is considered a major one under EPA regulations?
• When gas is compressed into a smaller space, what happens to the heat?
• Which principle is observed when gas molecules collide elastically in a closed system?
• What characterizes HCs as refrigerants?
• Which refrigerant is typically used in absorption refrigeration systems?
• At constant volume, the absolute pressure of a gas varies directly with which of the following?
• What type of recovery equipment relies on the compressor in the appliance or the refrigerant pressure?
• Why is it important not to mix different refrigerants in the same container?
• Which refrigerants are safe to mix together?
• When should personal protective equipment (gloves, safety glasses, safety shoes, etc) be worn?
• What device helps indicate that a refrigerant cylinder has reached its maximum safe fill level?
• In terms of efficiency, why is it important to maintain proper refrigerant charge in a system?
• What precaution should be taken when operating refrigerant recovery or recycling equipment?
• What type of refrigerant is characterized by being used and then released to the atmosphere?
• Which of the following statements is true regarding the recovery of refrigerants?
• What refrigerant is commonly used as a replacement for R-11?
• What is required by DOT when transporting cylinders containing used refrigerant?
• R11 or R123 system refrigerant recovery starts with?
• Which refrigerant is considered non-toxic and is primarily used in new automotive applications?
• Moisture most frequently enters low pressure chillers through which source?
• For an appliance containing 10 pounds of CFC-500 manufactured before November 15, 1993, to what level must it be evacuated before disposal?
• What level must technicians evacuate low pressure appliances to before making a major repair if the equipment is from before November 15, 1993?
• Which factors affect the speed of evacuation?
• A ton of refrigeration is equal to ______.
• When using vapor recovery, the fill level of the recovery cylinder can be controlled by?
• What is the ultimate goal of the recovery process in HVACR systems?
• Which law states that equal volumes of gases at equal pressures and temperatures contain equal numbers of molecules?
• In SI units, pressure above atmospheric pressure is primarily measured in ____.
• The state of refrigerant leaving the receiver of a refrigeration system is typically?
• In a zeotropic refrigerant blend, the refrigerant with the lowest boiling point boils first.
• Refrigeration can be described as ______.
• What is the superheat of a system if the refrigerant temperature in the suction line is 58°F and its temperature in the evaporator is 34°F with pressure in the evaporator at 60 psig?
• Carbon dioxide is classified as an organic refrigerant (600 series).
• What is the consequence of using a very short service line during vacuum operations?
• What is the typical evacuation level for high-pressure systems compared to low-pressure systems?
• What is the sum of the pressures for each gas in a confined mixture known as?
• What occurs if the force applied to an area increases?
• What is the effect on recovery time during low ambient temperatures?
• What principle states that in a mixture of gases, each gas exerts its own pressure independently?
• To clean refrigerant by the use of filter dryers is called ____.
• Which of the following refrigerants is classified as an HFC?
• If a refrigerant belongs to the 700 series in the refrigerant numbering system, it is classified as what type?
• A hydrostatic Tube Test Kit will?
• Which type of refrigerants use synthetic oils for lubrication because they cannot be mixed with mineral oils?
• What pressure type is indicated by the term 'low-pressure' when fixing a leak?
• A centrifugal chillers rupture disk is connected to the chiller's ______.
• Does Boyle's law state that if the volume of a gas increases, then its pressure increases?
• What is the status of selling CFC and HCFC refrigerants?
• Refrigerants that are blends of two gases to create a stable third refrigerant are known as what?
• What should a technician verify about recovery equipment before use?
• What type of refrigerant typically has a higher toxicity compared to others mentioned?
• What is the result of not properly evacuating an appliance before making a major repair?
• What is the primary function of the condenser in a refrigeration system?
• Which of the following gases helps form the earth's protective shield?
• What is not true about recycling and recovery equipment manufactured after November 15, 1993?
• R-500 is classified as what type of refrigerant?
• Is a perfect vacuum measured as 0 psig?
• Pressure below atmospheric pressure is primarily measured in ____.
• What is a routine maintenance task required on most refrigerant recycling machines?
• In refrigerant systems, low-side pressure gauges typically monitor what pressure?
• In the context of HVACR systems, what does 'active recovery' involve?
• At normal room temperatures, what is the pressure of a storage cylinder of recovered R22?
• Which refrigerants were targeted first for phaseout by the Montreal Protocol due to their high ozone depletion potential?
• What does the term "latent heat" refer to in refrigeration?
• Are solids and liquids generally compressible like gases in most cases?
• To remove the refrigerant from a system without any testing or processing to be put back into the same system is called ____.
• Which tool is commonly used for capturing refrigerant during recovery?
• What happens to the pressure if the volume of a gas increases while temperature is held constant?
• During the refrigeration cycle, what is the function of the compressor?
• According to Pascal's Law, how is pressure transmitted in a confined fluid?
• If the entire refrigerant charge has leaked out of a system, then a(n) ____ should be used to pressurize the system to test for leaks.
• What is a primary concern when recycling refrigerants under specific regulations?
• What is the PRIMARY purpose of a purge unit on a CFC-11 chiller?
• Which gas law would apply when analyzing an isothermal process?
• The critical temperature of a substance is the highest temperature at which the substance may be in a ____ state, regardless of the pressure applied to it.
• The process of separating individual refrigerants in a zeotropic blend during phase change is known as what?
• Which relationship is the foundation for controlling the cooling system's temperatures?
• Which refrigerant is typically associated with a pressure of approximately 130 psig at room temperature?
• Which gas law is fundamental to understanding refrigeration cycles?
• According to the ASHRAE classification for refrigerants, which classification represents the least toxic and least flammable refrigerants?
• What does DOT require when transporting cylinders containing used refrigerant?
• What term is used to describe pressure that is greater than atmospheric pressure?
• What characteristic is unique to zeotropic blends?
• If applied pressure on a saturated vapor is increased, then ____.
• What is the requirement for recovery devices manufactured before November 15, 1993?
• What is the main purpose of a refrigeration system's evaporator coil?
• Which federal act governs the regulations concerning the ozone layer protection?
• A refrigerant blend containing an HCFC and a CFC is considered a CFC.
• Which of the following would NOT fall under the EPA definition of "major maintenance, service, or repair"?
• Which characteristic is true for all CFC refrigerants?
• When using recovery or recycling equipment manufactured after November 15, 1993, technicians must evacuate low pressure appliances to which level before disposal?
• Calculate the tare weight of a cylinder if its total weight is 590 lb, and the weight of refrigerant in the cylinder is 450 lb.
• Which term describes extremely low refrigerant temperatures?
• During push-pull liquid recovery, vapor refrigerant is pulled from the ____.
• Which component in a refrigeration system converts a high pressure vapor to a high pressure liquid?
• Why is it important to use low-pressure nitrogen while fixing a leak?
• What is the color code for cylinders containing R-22?
• What best describes the behavior of a gas in a container?
• Cylinder color-coding is a requirement for manufacturers, so technicians do not need to check labels.
• What is a consequence of allowing air into a refrigerant system?
• What is the primary function of refrigerants in a refrigeration system?
• Reciprocating compressors have ______.
• When inspecting a hermetic system known to be leaking, what should you primarily look for?
• Which substance is classified as a non-condensable in refrigeration systems?
• When preparing for a leak repair in an HVACR system, what gas should be utilized to avoid contamination?
• According to Gay-Lussac's Law, if the absolute temperature of a gas increases, what happens to the absolute pressure?
• What principle does refrigeration commonly rely on?
• What is the maximum award amount for information leading to penalties against technicians intentionally venting refrigerant?
• Before performing brazing to fix a leak, what is essential to prevent system contamination?
• Where should a leak detector probe be placed to check for leaks into the water box with water removed?
• What should be maintained in a system before a leak repair is made through brazing?
• What occurs when room temperature soda is introduced into a glass of ice?
• Subcooling refers to the amount of which type of heat removed from a refrigerant after it has condensed?
• Which of the following safety precautions should be adhered to for low pressure systems?
• What is the primary purpose of the expansion valve in a refrigeration system?
• What is the synthetic lubricant presently used with ternary blends containing HCFCs?
• Which law explains the relationship between pressure and temperature at constant volume?
• In thermodynamics, what is the effect of increasing pressure on the boiling point of a liquid?
• What is the ideal temperature for the refrigerator's fresh food section?
• According to EPA's regulations, what method can be used to pressurize an R11 or R123 system for non-major repairs?
• Which refrigerants are typically required to be controlled due to their environmental impact?
• Which of the following refrigerants is considered an ozone-depleting substance?
• Why is it required by law for technicians to recover refrigerants from refrigeration systems?
• Good ventilation is important when working around refrigeration equipment because modern refrigerants ______.
• If applied pressure on a saturated vapor is decreased, then ____.
• Ozone depletion in the stratosphere is classified as what type of problem?
• Which of the following is necessary for effective evacuation of the system?
• If a system is opened for servicing, which component should be replaced?
• HCFCs have an ODP rating of 0.
• How many times can an expendable refrigerant be used?
• Why might recycling or recovery equipment with hermetic compressors overheat when drawing deep vacuums?
• What must some state and local laws do regarding EPA regulations?
• Can pressures below atmospheric pressure be measured in inches of mercury column?
• In what scenario is it advisable to use recovery equipment with a higher capacity?
• In a refrigeration system, the evaporator's role is to ______.
• Can service technicians safely use formulas and tables to mix their own azeotropic refrigerant blends?
• Is it true or false that longer vacuum pump service lines are more effective at pulling a vacuum than shorter ones?
• EPA regulations require that leaking commercial and industrial process refrigeration be repaired when the leak rate exceeds ____________ percent of the charge each year.
• R-134a has been used as a replacement refrigerant for systems that use R-12.
• All devices used for refrigerant recovery must meet which requirements?
• To reprocess refrigerant to meet new product specifications is called ____.
• What is the evaporation temperature of R134A at 0 psig?
• HFCs were the first type of refrigerant to be produced.
• Which component is responsible for expanding the refrigerant's pressure in the refrigeration cycle?
• After 1995, supplies of CFC refrigerant for equipment servicing will come from?
• What should be done when installing an access fitting onto a sealed system?
• Which of the following repairs would ALWAYS be considered "major" under EPA's regulations?
• What is the purpose of the purge unit in a refrigeration system?
• What is the primary function of a condenser in a refrigeration system?
• Before recovering refrigerant from a unit with R22, what should you do if you have R503 in your recovery machine?
• Recovering refrigerant from a system in vapor phase minimizes the loss of what?
• What is the expected pressure of a storage cylinder of recovered R500 at normal room temperature?
• What may happen if a technician does not comply with updated EPA regulations after certification?
• The ozone depletion factor of R-12 is ____.
• If the area increases according to the pressure formula, what happens to the pressure?
• What is the abbreviation for refrigerants that contain chlorine, fluorine, and carbon?
• Which refrigerant is highly flammable and is often subject to careful handling?
• Portable refillable tanks or containers used to ship CFC or HCFC refrigerants must meet what standards?
• What relationship does a pressure-temperature curve indicate in a refrigeration system?
• What should be done if a refrigerant recovery procedure indicates oil contamination?
• High temperature refrigeration is that produced by ______.
• What commonality do chlorofluorocarbons and hydrochlorofluorocarbons share?
• What law states that the volume of a gas varies inversely to the pressure if temperature remains constant?
• The _____ takes into consideration both the direct and indirect global warming effects of refrigerants.
• Which law explains that a gas's volume is directly proportional to its absolute temperature when pressure is held constant?
• Under what code group of ASHRAE standard 34 does R123 fall?
• What is the difference between absolute pressure and gauge pressure?
• What can be done with refrigerant recovered from an air-conditioning system held in a refillable cylinder?
• How many chlorine atoms are needed to destroy 100,000 ozone molecules in the stratosphere?
• When pressurizing a refrigerant system with nitrogen, what rule should you always follow?
• What process involves removing refrigerant from a system and storing it without testing it?
• Which refrigerant is noted for having a low ODP, low GWP, and reduced toxicity?
• What occurs to refrigerant during the pump-down process?
• What role does the evaporator serve in a refrigeration system?
• Which gas law states that temperature remains constant while pressure and volume have an inverse relationship?
• Which law states that pressure remains constant while temperature and volume rise and fall together?
• A system should not contain what type of gas before brazing to repair a leak?
• Which of the following statements about vacuum pump service lines is accurate?
• Hydroflourocarbon refrigerants contain which of the following?
• What is the primary function of the compressor in an HVACR system?
• When high-side pressure readings are affected in an HVAC system due to trapped air, which law is applied?
• When changing out a compressor in a system with R502, what procedure should you follow if your recycling equipment was manufactured after November 15, 1993?
• The ozone layer primarily protects the Earth from which type of radiation?
• Why must water be circulated through a chiller during refrigerant evacuation?
• What is the relationship between pressure and volume in Boyle's Law?
• Which zeotropic refrigerant blend is used as a replacement for R-22 in air-conditioning applications, but operates at a higher temperature and pressure?
• Which of the following refrigerants is chlorine-free?
• As applied pressure is raised on water, its boiling point ____.
• When using recovery cylinders and equipment with Schrader valves, it is critical to?
• When can appliances containing CFC refrigerants be evacuated to atmospheric pressure?
• What should you do after reaching the required vacuum on an appliance?
• How is the amount of refrigerant charge typically expressed for a recovery cylinder?
• Which of the following refrigerants is classified as an HCFC?
• What is the lowest temperature at which a lubricant will flow called?
• Which evacuation method involves charging a system with nitrogen to absorb moisture?
• Refrigerant is added to the centrifugal machine through the?
• If heat is added to a saturated vapor and its temperature is raised above the boiling point, what is this heat referred to as?
• What type of leaks most commonly occur in the areas with gaskets or fittings in low-pressure systems?
• A higher coefficient of performance means that a refrigerant produces its refrigeration effect more efficiently.
• When a refrigeration unit is off, the temperature of the condenser is ____ the temperature of the refrigerant.
• What type of compressor uses two rotating scrolls to compress refrigerant?
• What is the purpose of self-sealing connectors on gauge set hoses?
• Which factor is least likely to affect refrigerant recovery effectiveness?
• What is the maximum amount of refrigerant that a recovery cylinder should contain?
• When the unit is running, is the refrigerant temperature equal to the evaporator temperature?
• What changes occur to refrigerant as it passes through the compressor?