CSN AC 110 ESCO Exam Practice – Latest Exam
Prep 2025/2026 | Air Conditioning Practice
Questions & Study Guide
1. Heat which causes a change in temperature of a substance is called;
A. latent heat
B. sensible heat
C. superheat
D. radiant heat - correct answerB. sensible heat
2. Heat added to a substance without a raise in temperature; (example: liquid refrigerant
to gas) this process is called?
A. latent heat of vaporization
B. latent heat of fusion.
C. superheat of vaporization
D. superheat of fusion - correct answerA. latent heat of vaporization
3. Heat added to the refrigerant in a vapor state after the evaporation process is called;
A. latent heat
B. subcooling
C. superheat
D. specific heat - correct answerC. superheat
4. A scroll compressor move refrigerant by means of;
A. a piston
B. an impeller
C. vane and cam
D. involute spirals - correct answerD. involute spirals
5. The movement of heat by way of fluid (or air) is called;
A. conduction
B. convection
C. radiation
D. percussion - correct answerB. convection
6. The movement of heat through a solid object is called;
A. conduction
B. convection
C. radiation
D. compression - correct answerA. conduction
7. The standard unit for measuring the quantity of heat in a substance is;
,A. degrees Fahrenheit
B. degrees Celsius
C. degrees Rankin
D. the British Thermal Unit (Btu) - correct answerD. the British Thermal Unit (Btu)
8. A refrigerant gives up heat when;
A. it condenses
B. it evaporates
C. it is compressed
D. it vaporizes - correct answerA. it condenses
9. Why must refrigerant in the suction line be slightly warmer than the saturation
temperature?
A. prevent liquid slugging of hte compressor
B. prevent refrigerant vapor lock
C. prevent the compressor from overheating
D. prevent oil miscibility - correct answerA. prevent liquid slugging of the compressor
10. The state of the refrigerant in the suction line should be;
A. high pressure / high temperature liquid
B high pressure / low temperature vapor
C. low pressure / low temperature liquid
D. low pressure / low temperature vapor - correct answerD. low pressure / low
temperature vapor
11. The state of the refrigerant entering the condenser is;
A. high temperature / highly superheated liquid
B. high pressure / highly superheated vapor
C. high pressure / high temperature liquid
D. low pressure / low temperature vapor - correct answerB. high pressure / highly
superheated vapor
12. the evaporator;
A. transfers heat from the refrigerated space to the refrigerant
B. transfers heat from the refrigerant to the refrigerated space
C. transfers heat from the refrigerant to the ambient air
D. transfers heat from the ambient air to the refrigerated space - correct answerA.
transfers heat from the refrigerated space to the refrigerant
13. Which of the following is not a thermodynamic property of refrigerants?
A. critical point
B. saturation point
C. enthalpy
D. flammability - correct answerD. flammability
14. The sequential order of steps in the vapor - compression process are;
, A. expansion, condensation, compression, vaporization
B. vaporization, expansion, condensation, compression
C. compression, condensation, expansion, vaporization
D. expression, compression, vaporization, condensation - correct answerC.
compression, condensation, expansion, vaporization
15. If a 30 pound cylinder of reclaimed R-410A refrigerant has been stored over night at
70°F, the pressure of the cylinder shoudl be approximately:
A. 201 psig
B. 168 psig
C. 143 psig
D. 118 psig - correct answerA. 201 psig
16. Fan airflow pressures are usually measured in;
A. inches of mercury vacuum or micorns
B. microns or psig
C. psig or inches of mercury vacuum
D. inches of water column (WC) - correct answerD. inches of water column (WC)
17. Zero psia (pounds per square inch absolute) is;
A. the same as atmospheric pressure
B. approximately 14.7 psig at sea level
C. a pressure which cannot be further reduced
D. equal to 500 microns - correct answerB. approximately 14.7 psig at sea level
18. zero psig (Pounds per squeare indch gauge is;
A. 25,400 microns
B. approximately 29.9 psia at sea-level
C. a pressure which cannot be further reduced
D. the same as atmospheric pressure - correct answerD. the same as atmospheric
pressure
19. The temperature at which moisture will start to condense from the air is called;
A. dry bulb temperature
B. wet buldb dry depression
C. dew point temperature
D. condensate point - correct answerC. dew point temperature
20. A compound pressure gauge measures;
A. pressure and vacuum
B. pressure and temperature
C. pressure and humidity
D. wet and dry bulb temperatures - correct answerA. pressure and vacuum
21. A mechanical shaft seal is necessary on a;
A. semi-hermetic compressor
Prep 2025/2026 | Air Conditioning Practice
Questions & Study Guide
1. Heat which causes a change in temperature of a substance is called;
A. latent heat
B. sensible heat
C. superheat
D. radiant heat - correct answerB. sensible heat
2. Heat added to a substance without a raise in temperature; (example: liquid refrigerant
to gas) this process is called?
A. latent heat of vaporization
B. latent heat of fusion.
C. superheat of vaporization
D. superheat of fusion - correct answerA. latent heat of vaporization
3. Heat added to the refrigerant in a vapor state after the evaporation process is called;
A. latent heat
B. subcooling
C. superheat
D. specific heat - correct answerC. superheat
4. A scroll compressor move refrigerant by means of;
A. a piston
B. an impeller
C. vane and cam
D. involute spirals - correct answerD. involute spirals
5. The movement of heat by way of fluid (or air) is called;
A. conduction
B. convection
C. radiation
D. percussion - correct answerB. convection
6. The movement of heat through a solid object is called;
A. conduction
B. convection
C. radiation
D. compression - correct answerA. conduction
7. The standard unit for measuring the quantity of heat in a substance is;
,A. degrees Fahrenheit
B. degrees Celsius
C. degrees Rankin
D. the British Thermal Unit (Btu) - correct answerD. the British Thermal Unit (Btu)
8. A refrigerant gives up heat when;
A. it condenses
B. it evaporates
C. it is compressed
D. it vaporizes - correct answerA. it condenses
9. Why must refrigerant in the suction line be slightly warmer than the saturation
temperature?
A. prevent liquid slugging of hte compressor
B. prevent refrigerant vapor lock
C. prevent the compressor from overheating
D. prevent oil miscibility - correct answerA. prevent liquid slugging of the compressor
10. The state of the refrigerant in the suction line should be;
A. high pressure / high temperature liquid
B high pressure / low temperature vapor
C. low pressure / low temperature liquid
D. low pressure / low temperature vapor - correct answerD. low pressure / low
temperature vapor
11. The state of the refrigerant entering the condenser is;
A. high temperature / highly superheated liquid
B. high pressure / highly superheated vapor
C. high pressure / high temperature liquid
D. low pressure / low temperature vapor - correct answerB. high pressure / highly
superheated vapor
12. the evaporator;
A. transfers heat from the refrigerated space to the refrigerant
B. transfers heat from the refrigerant to the refrigerated space
C. transfers heat from the refrigerant to the ambient air
D. transfers heat from the ambient air to the refrigerated space - correct answerA.
transfers heat from the refrigerated space to the refrigerant
13. Which of the following is not a thermodynamic property of refrigerants?
A. critical point
B. saturation point
C. enthalpy
D. flammability - correct answerD. flammability
14. The sequential order of steps in the vapor - compression process are;
, A. expansion, condensation, compression, vaporization
B. vaporization, expansion, condensation, compression
C. compression, condensation, expansion, vaporization
D. expression, compression, vaporization, condensation - correct answerC.
compression, condensation, expansion, vaporization
15. If a 30 pound cylinder of reclaimed R-410A refrigerant has been stored over night at
70°F, the pressure of the cylinder shoudl be approximately:
A. 201 psig
B. 168 psig
C. 143 psig
D. 118 psig - correct answerA. 201 psig
16. Fan airflow pressures are usually measured in;
A. inches of mercury vacuum or micorns
B. microns or psig
C. psig or inches of mercury vacuum
D. inches of water column (WC) - correct answerD. inches of water column (WC)
17. Zero psia (pounds per square inch absolute) is;
A. the same as atmospheric pressure
B. approximately 14.7 psig at sea level
C. a pressure which cannot be further reduced
D. equal to 500 microns - correct answerB. approximately 14.7 psig at sea level
18. zero psig (Pounds per squeare indch gauge is;
A. 25,400 microns
B. approximately 29.9 psia at sea-level
C. a pressure which cannot be further reduced
D. the same as atmospheric pressure - correct answerD. the same as atmospheric
pressure
19. The temperature at which moisture will start to condense from the air is called;
A. dry bulb temperature
B. wet buldb dry depression
C. dew point temperature
D. condensate point - correct answerC. dew point temperature
20. A compound pressure gauge measures;
A. pressure and vacuum
B. pressure and temperature
C. pressure and humidity
D. wet and dry bulb temperatures - correct answerA. pressure and vacuum
21. A mechanical shaft seal is necessary on a;
A. semi-hermetic compressor
