EPA 608 TYPE III – COMPREHENSIVE EXAM PREP - Section
608 Low-Pressure Appliance Certification Practice Test Bank
2026-2027
Pass your Environmental Protection Agency Type III low-pressure appliance technician
validation on your very first attempt with this definitive Section 608 certification
preparation bank. This comprehensive study guide features high-yield practice
questions paired with 100% verified answers and detailed mechanical rationales
covering leak detection requirements, recovery techniques, evacuation levels, and
safety protocols unique to low-pressure chillers. It is an indispensable resource for
HVAC/R technicians, commercial facility mechanics, and trade students looking to
eliminate test anxiety, master clean air regulations, and secure their official credential.
1. When recovering liquid refrigerant from a low-pressure chiller, where is the
liquid refrigerant typically found?
A. In the compressor oil sump
B. In the purge unit receiver
C. At the bottom of the evaporator
D. In the condenser water boxes
Rationale: In a low-pressure chiller, liquid refrigerant pools at the bottom of the
evaporator. The technician must recover this liquid first before attempting vapor recovery.
Failing to recover liquid first can cause liquid slugging in the recovery compressor.
2. What is the maximum permissible pressure for a low-pressure chiller during a
leak test before the rupture disc activates?
A. 5 psig
B. 10 psig
C. 15 psig
D. 20 psig
Rationale: While the rupture disc typically relieves at 15 psig, the safe maximum test
pressure is 10 psig. Pressurizing to 15 psig could cause the disc to burst, requiring
replacement and loss of refrigerant charge.
,3. A technician is preparing to evacuate a low-pressure chiller. What is the
recommended pressure for a standing vacuum test to check for leaks?
A. 1 mm Hg absolute
B. 2.5 mm Hg absolute
C. 5 inches Hg vacuum
D. 25 inches Hg vacuum
Rationale: ASHRAE Guideline 3 recommends performing a standing vacuum test at 1 mm
Hg, with a pressure rise to 2.5 mm Hg indicating a leak. If the pressure remains below 2.5
mm Hg, the system is considered tight.
4. What is the typical purge unit suction location on a low-pressure chiller?
A. The bottom of the evaporator
B. The compressor discharge line
C. The top of the condenser
D. The liquid line receiver
Rationale: Air and non-condensable gases collect at the highest point in the system—the
top of the condenser—because they are lighter than refrigerant vapor. The purge unit
draws suction from this point to remove these contaminants.
5. Which refrigerant is a high-pressure refrigerant requiring Type II certification,
NOT Type III?
A. R-123
B. *R-22*
C. R-11
D. R-113
Rationale: R-22 is a high-pressure refrigerant used in medium-temperature systems and
requires Type II certification. R-123, R-11, and R-113 are low-pressure refrigerants
operating below atmospheric pressure, which require Type III certification.
,6. A technician is recovering refrigerant from a low-pressure chiller that contains
500 pounds of R-123. What is the approximate weight of refrigerant that will
remain as vapor after liquid recovery?
A. 5 pounds
B. 100 pounds
C. 250 pounds
D. 400 pounds
Rationale: Based on EPA estimates, approximately 100 pounds of refrigerant vapor
remains in a typical 350-ton low-pressure chiller at 0 psig after liquid recovery. For a
larger system, the vapor remaining would be proportional, but the key concept is that
significant vapor remains.
7. When is a technician required to calculate the leak rate on a low-pressure
chiller?
A. After any preventive maintenance
B. Whenever refrigerant is added to the system
C. Only when the system is retired
D. During annual inspections only
Rationale: The EPA requires a leak rate calculation whenever refrigerant is added due to a
leak. Topping off or adding refrigerant implies that refrigerant has been lost and must be
accounted for in leak rate calculations.
8. What is the correct order of operations when recharging an evacuated low-
pressure chiller?
A. Add liquid refrigerant through the evaporator charging valve
B. Add vapor refrigerant until the system pressure corresponds to 36°F saturation
temperature, then add liquid
, C. Add nitrogen to break the vacuum
D. Start the compressor before adding refrigerant
Rationale: Vapor must be added first to raise the system pressure to prevent water in the
heat exchanger from freezing. Once the pressure is raised to the saturation temperature of
36°F, liquid refrigerant can be added through the evaporator charging valve.
9. What is the proper method for checking a low-pressure chiller for tube leaks in
the evaporator water box?
A. Pressurize the water box to 50 psig with air
B. Drain the water side, pressurize the refrigerant side to 10 psig, and place a leak
detector probe at the water box drain
C. Add refrigerant dye to the water side
D. Visually inspect the tube sheet
Rationale: To test for tube leaks, the water side must be drained and the refrigerant side
gently pressurized (not exceeding 10 psig). A leak detector probe at the drain port will
detect refrigerant vapor if a tube is leaking. The water box can also be pressurized with air
to check for leaks.
10. A technician is setting up a recovery machine for a low-pressure chiller. What is
the primary water source for the recovery unit condensing coil?
A. The chiller's chilled water supply
B. The condenser water return
C. Local municipal water supply
D. De-ionized water
Rationale: The recovery unit condensing coil typically uses local municipal water supply as
the primary cooling source. This water absorbs heat from the refrigerant vapor as it
condenses back to liquid during the recovery process.
608 Low-Pressure Appliance Certification Practice Test Bank
2026-2027
Pass your Environmental Protection Agency Type III low-pressure appliance technician
validation on your very first attempt with this definitive Section 608 certification
preparation bank. This comprehensive study guide features high-yield practice
questions paired with 100% verified answers and detailed mechanical rationales
covering leak detection requirements, recovery techniques, evacuation levels, and
safety protocols unique to low-pressure chillers. It is an indispensable resource for
HVAC/R technicians, commercial facility mechanics, and trade students looking to
eliminate test anxiety, master clean air regulations, and secure their official credential.
1. When recovering liquid refrigerant from a low-pressure chiller, where is the
liquid refrigerant typically found?
A. In the compressor oil sump
B. In the purge unit receiver
C. At the bottom of the evaporator
D. In the condenser water boxes
Rationale: In a low-pressure chiller, liquid refrigerant pools at the bottom of the
evaporator. The technician must recover this liquid first before attempting vapor recovery.
Failing to recover liquid first can cause liquid slugging in the recovery compressor.
2. What is the maximum permissible pressure for a low-pressure chiller during a
leak test before the rupture disc activates?
A. 5 psig
B. 10 psig
C. 15 psig
D. 20 psig
Rationale: While the rupture disc typically relieves at 15 psig, the safe maximum test
pressure is 10 psig. Pressurizing to 15 psig could cause the disc to burst, requiring
replacement and loss of refrigerant charge.
,3. A technician is preparing to evacuate a low-pressure chiller. What is the
recommended pressure for a standing vacuum test to check for leaks?
A. 1 mm Hg absolute
B. 2.5 mm Hg absolute
C. 5 inches Hg vacuum
D. 25 inches Hg vacuum
Rationale: ASHRAE Guideline 3 recommends performing a standing vacuum test at 1 mm
Hg, with a pressure rise to 2.5 mm Hg indicating a leak. If the pressure remains below 2.5
mm Hg, the system is considered tight.
4. What is the typical purge unit suction location on a low-pressure chiller?
A. The bottom of the evaporator
B. The compressor discharge line
C. The top of the condenser
D. The liquid line receiver
Rationale: Air and non-condensable gases collect at the highest point in the system—the
top of the condenser—because they are lighter than refrigerant vapor. The purge unit
draws suction from this point to remove these contaminants.
5. Which refrigerant is a high-pressure refrigerant requiring Type II certification,
NOT Type III?
A. R-123
B. *R-22*
C. R-11
D. R-113
Rationale: R-22 is a high-pressure refrigerant used in medium-temperature systems and
requires Type II certification. R-123, R-11, and R-113 are low-pressure refrigerants
operating below atmospheric pressure, which require Type III certification.
,6. A technician is recovering refrigerant from a low-pressure chiller that contains
500 pounds of R-123. What is the approximate weight of refrigerant that will
remain as vapor after liquid recovery?
A. 5 pounds
B. 100 pounds
C. 250 pounds
D. 400 pounds
Rationale: Based on EPA estimates, approximately 100 pounds of refrigerant vapor
remains in a typical 350-ton low-pressure chiller at 0 psig after liquid recovery. For a
larger system, the vapor remaining would be proportional, but the key concept is that
significant vapor remains.
7. When is a technician required to calculate the leak rate on a low-pressure
chiller?
A. After any preventive maintenance
B. Whenever refrigerant is added to the system
C. Only when the system is retired
D. During annual inspections only
Rationale: The EPA requires a leak rate calculation whenever refrigerant is added due to a
leak. Topping off or adding refrigerant implies that refrigerant has been lost and must be
accounted for in leak rate calculations.
8. What is the correct order of operations when recharging an evacuated low-
pressure chiller?
A. Add liquid refrigerant through the evaporator charging valve
B. Add vapor refrigerant until the system pressure corresponds to 36°F saturation
temperature, then add liquid
, C. Add nitrogen to break the vacuum
D. Start the compressor before adding refrigerant
Rationale: Vapor must be added first to raise the system pressure to prevent water in the
heat exchanger from freezing. Once the pressure is raised to the saturation temperature of
36°F, liquid refrigerant can be added through the evaporator charging valve.
9. What is the proper method for checking a low-pressure chiller for tube leaks in
the evaporator water box?
A. Pressurize the water box to 50 psig with air
B. Drain the water side, pressurize the refrigerant side to 10 psig, and place a leak
detector probe at the water box drain
C. Add refrigerant dye to the water side
D. Visually inspect the tube sheet
Rationale: To test for tube leaks, the water side must be drained and the refrigerant side
gently pressurized (not exceeding 10 psig). A leak detector probe at the drain port will
detect refrigerant vapor if a tube is leaking. The water box can also be pressurized with air
to check for leaks.
10. A technician is setting up a recovery machine for a low-pressure chiller. What is
the primary water source for the recovery unit condensing coil?
A. The chiller's chilled water supply
B. The condenser water return
C. Local municipal water supply
D. De-ionized water
Rationale: The recovery unit condensing coil typically uses local municipal water supply as
the primary cooling source. This water absorbs heat from the refrigerant vapor as it
condenses back to liquid during the recovery process.
