EPA Study Guide Type III with Complete Solutions
1. A typical setting for the high pressure cut-out system, this indicates that the __________.
control on a recovery unit used for evacuating A) the system was charged with contaminated
the refrigerant from a low pressure chiller is: refrigerant.
A) 2 psig. B) the condenser or chiller barrel tubes are
B) 5 psig. leaking.
C) 10 psig. C) the purge unit is not operating properly.
D) 15 psig - -Answer: C D) the purge unit needs adjustment. - -
Answer: B
2. A charged low pressure refrigeration system
can be efficiently leak checked by: 7. ASHRAE Standard 15 - 1994 requires
A) adding compressed air, since it will be equipment room refrigerant sensors for what
removed from the system by the Purging unit. safety group classification?
B) operating the purge system. A) A1
C) adding HCFC-22. B) B2
D) raising system pressure by heating with C) A2
circulated hot water or heating blankets. - - D) All refrigerant safety groups - -Answer:
Answer: D D
3. The existence of air in a low pressure system, 8. When recharging a refrigeration system with
causes __________. R-11, what vapor pressure is necessary in the
A) low head pressure. shells before charging with liquid?
B) low suction pressure. A) 21.1" Hg vacuum
C) high head pressure. B) 19.7" Hg vacuum
D) high liquid level - -Answer: C C) 18.1" Hg vacuum
D) 16.9" Hg vacuum - -Answer: D
4. Which safety precaution should be adhered to
for low pressure systems? 9. After reaching the required recovery vacuum
A) Do not siphon refrigerant by mouth. on a chiller, you should:
B) Avoid spilling liquid refrigerant on the skin. A) Immediately disconnect the recycling or
C) Use gloves and safety goggles when working recovery equipment and open the system for
with liquid refrigerant. service.
D) all of the above - -Answer: D B) Wait for at least a few minutes to see if the
system pressure rises, indicating that there is still
refrigerant in liquid form or in the oil.
5. Refrigerant-11 at 14.7 PSIA will boil at about: C) Immediately break the vacuum with nitrogen
A) 60.3F. and open the system for service.
B) 74.5F. D) Immediately pressurize the system with
C) 79.7F. nitrogen and perform a leak check. - -
D) 80.2F. - -Answer: B Answer: B
6. When there is excessive moisture collecting in 10. A hydrostatic tube test kit is used to:
the purge unit of a low pressure refrigeration A) blow all water from the tubes.
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, EPA Study Guide Type III with Complete Solutions
B) remove any water from the machine.
C) vent refrigerant. 15. Commercial and industrial process
D) determine if a tube leaks. - -Answer: D refrigeration systems must be repaired when the
leak rate exceeds ______ percent of the charge
per year.
11. When charging a chiller, refrigerant vapor is A) 5%
introduced into the system before charging with B) 15%
liquid. This is because: C) 20%
A) Vapor charging increases pressure slowly, D) 35% - -Answer: D
preventing failure of the rupture disk.
B) Vapor charging is faster than liquid charging.
C) Liquid charging is more difficult to control than 16. When recovering vapor from a low pressure
vapor charging. refrigeration system the:
D) Liquid charged into a deep vacuum will cause A) water pumps should be on, and the recovery
the refrigerant to boil and may lower compressor should be off.
temperatures enough to freeze the water in the B) system water pumps should be on, the
tubes. - -Answer: D recovery compressor should be on, and the
recovery condenser water should be off.
C) system water pumps, the recovery
12. When evacuating a system, the use of too compressor, and the recovery condenser water
large a vacuum pump can cause: should all be on.
A) trapped water to freeze. D) system water pumps should be off, and the
B) trapped oil to freeze. recovery compressor should be on. - -
C) trapped refrigerant to freeze. Answer: C
D) valves to freeze. - -Answer: A
17. Where does refrigerant go after it leaves the
13. On a low-pressure chiller with an open-type purge unit of a low pressure centrifugal system?
compressor, the ________________ is very A) the evaporator
susceptible to leaks. B) the condenser
A) chiller tubes C) the compressor intercooler
B) shaft seal D) the recovery service vessel - -Answer: A
C) charging connections
D) shaft bearings - -Answer: B
18. The purge unit takes its suction from the:
A) top of the condenser.
14. What steps may be taken to prevent air B) compressor oil sump.
accumulation into an idle low pressure C) top of the evaporator.
refrigeration system? D) suction elbow. - -Answer: A
A) Leave the purge unit on-line at all times.
B) System pressure should be maintained
slightly above atmospheric. 19. Which of the following repairs would
C) Open the air vents on the condenser. ALWAYS be considered "major" under EPA's
D) Intermittently operate the system with no load. regulations?
- -Answer: B A) replacement of an evaporator coil
B) replacement of a filter-drier
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1. A typical setting for the high pressure cut-out system, this indicates that the __________.
control on a recovery unit used for evacuating A) the system was charged with contaminated
the refrigerant from a low pressure chiller is: refrigerant.
A) 2 psig. B) the condenser or chiller barrel tubes are
B) 5 psig. leaking.
C) 10 psig. C) the purge unit is not operating properly.
D) 15 psig - -Answer: C D) the purge unit needs adjustment. - -
Answer: B
2. A charged low pressure refrigeration system
can be efficiently leak checked by: 7. ASHRAE Standard 15 - 1994 requires
A) adding compressed air, since it will be equipment room refrigerant sensors for what
removed from the system by the Purging unit. safety group classification?
B) operating the purge system. A) A1
C) adding HCFC-22. B) B2
D) raising system pressure by heating with C) A2
circulated hot water or heating blankets. - - D) All refrigerant safety groups - -Answer:
Answer: D D
3. The existence of air in a low pressure system, 8. When recharging a refrigeration system with
causes __________. R-11, what vapor pressure is necessary in the
A) low head pressure. shells before charging with liquid?
B) low suction pressure. A) 21.1" Hg vacuum
C) high head pressure. B) 19.7" Hg vacuum
D) high liquid level - -Answer: C C) 18.1" Hg vacuum
D) 16.9" Hg vacuum - -Answer: D
4. Which safety precaution should be adhered to
for low pressure systems? 9. After reaching the required recovery vacuum
A) Do not siphon refrigerant by mouth. on a chiller, you should:
B) Avoid spilling liquid refrigerant on the skin. A) Immediately disconnect the recycling or
C) Use gloves and safety goggles when working recovery equipment and open the system for
with liquid refrigerant. service.
D) all of the above - -Answer: D B) Wait for at least a few minutes to see if the
system pressure rises, indicating that there is still
refrigerant in liquid form or in the oil.
5. Refrigerant-11 at 14.7 PSIA will boil at about: C) Immediately break the vacuum with nitrogen
A) 60.3F. and open the system for service.
B) 74.5F. D) Immediately pressurize the system with
C) 79.7F. nitrogen and perform a leak check. - -
D) 80.2F. - -Answer: B Answer: B
6. When there is excessive moisture collecting in 10. A hydrostatic tube test kit is used to:
the purge unit of a low pressure refrigeration A) blow all water from the tubes.
1/7
, EPA Study Guide Type III with Complete Solutions
B) remove any water from the machine.
C) vent refrigerant. 15. Commercial and industrial process
D) determine if a tube leaks. - -Answer: D refrigeration systems must be repaired when the
leak rate exceeds ______ percent of the charge
per year.
11. When charging a chiller, refrigerant vapor is A) 5%
introduced into the system before charging with B) 15%
liquid. This is because: C) 20%
A) Vapor charging increases pressure slowly, D) 35% - -Answer: D
preventing failure of the rupture disk.
B) Vapor charging is faster than liquid charging.
C) Liquid charging is more difficult to control than 16. When recovering vapor from a low pressure
vapor charging. refrigeration system the:
D) Liquid charged into a deep vacuum will cause A) water pumps should be on, and the recovery
the refrigerant to boil and may lower compressor should be off.
temperatures enough to freeze the water in the B) system water pumps should be on, the
tubes. - -Answer: D recovery compressor should be on, and the
recovery condenser water should be off.
C) system water pumps, the recovery
12. When evacuating a system, the use of too compressor, and the recovery condenser water
large a vacuum pump can cause: should all be on.
A) trapped water to freeze. D) system water pumps should be off, and the
B) trapped oil to freeze. recovery compressor should be on. - -
C) trapped refrigerant to freeze. Answer: C
D) valves to freeze. - -Answer: A
17. Where does refrigerant go after it leaves the
13. On a low-pressure chiller with an open-type purge unit of a low pressure centrifugal system?
compressor, the ________________ is very A) the evaporator
susceptible to leaks. B) the condenser
A) chiller tubes C) the compressor intercooler
B) shaft seal D) the recovery service vessel - -Answer: A
C) charging connections
D) shaft bearings - -Answer: B
18. The purge unit takes its suction from the:
A) top of the condenser.
14. What steps may be taken to prevent air B) compressor oil sump.
accumulation into an idle low pressure C) top of the evaporator.
refrigeration system? D) suction elbow. - -Answer: A
A) Leave the purge unit on-line at all times.
B) System pressure should be maintained
slightly above atmospheric. 19. Which of the following repairs would
C) Open the air vents on the condenser. ALWAYS be considered "major" under EPA's
D) Intermittently operate the system with no load. regulations?
- -Answer: B A) replacement of an evaporator coil
B) replacement of a filter-drier
2/7
