EPA 608 TYPE III CERTIFICATION EXAM
EPA 608 TYPE III CERTIFICATION EXAM STUDY
GUIDE: LOW-PRESSURE REFRIGERATION
SYSTEMS, CE, 2026/2027
A technician is preparing to service a large centrifugal chiller containing
R-123. The technician needs to open the refrigerant circuit for a major
repair. Which certification is specifically intended for servicing this type
of low-pressure appliance?
A) Type I
B) Type II
C) Type III
D) Type V
✓✓ Correct Answer: C) Type III
Rationale: EPA Section 608 Type III certification is intended for
technicians who service or dispose of low-pressure appliances.
Centrifugal chillers are a key example of equipment associated with
low-pressure refrigeration. Type I certification covers small appliances,
while Type II covers high- and very high-pressure appliances other than
small appliances and MVACs. Universal certification covers all
equipment categories. A technician must hold the appropriate
certification for the work being performed, and an EPA-approved
certification examination is required.
A technician measures the pressure in a centrifugal chiller and finds that
the system is operating below atmospheric pressure. Which condition is
most likely to occur if the system develops a leak?
A) Refrigerant automatically escapes rapidly into the atmosphere
1|Page
, EPA 608 TYPE III CERTIFICATION EXAM
B) Air and moisture may enter the system
C) The compressor immediately stops because of high discharge
pressure
D) The condenser pressure increases above atmospheric pressure
✓✓ Correct Answer: B) Air and moisture may enter the system
Rationale: Low-pressure refrigeration systems often operate below
atmospheric pressure on the evaporator side. When the pressure inside
the system is lower than the surrounding atmospheric pressure, a leak
can allow air and moisture to enter the system rather than refrigerant
escaping outward. Noncondensable gases can interfere with heat
transfer and raise condensing pressure, while moisture can contribute
to corrosion, freezing, and other system problems. This is why leak
detection and proper evacuation are important when servicing low-
pressure chillers. The technician should not assume that a low-pressure
system is leak-free simply because refrigerant is not visibly escaping.
A centrifugal chiller is suspected of leaking because the purge unit is
operating much more frequently than usual. What should the
technician recognize?
A) Excessive purge operation may indicate air or other noncondensables
entering the system
B) The purge unit proves that the compressor has failed
C) Frequent purge operation always indicates an overcharged system
D) The purge unit eliminates the need for leak testing
✓✓ Correct Answer: A) Excessive purge operation may indicate air or
other noncondensables entering the system
2|Page
, EPA 608 TYPE III CERTIFICATION EXAM
Rationale: A purge unit removes noncondensable gases, such as air,
from certain low-pressure refrigeration systems. Because low-pressure
chillers can draw air inward through leaks, an increase in purge activity
may be a warning sign of leakage or another source of
noncondensables. However, excessive purge operation does not prove a
particular leak location or cause. The technician should investigate the
system using appropriate leak-detection methods and evaluate purge
performance. Purging is not a substitute for repairing leaks, and the
presence of noncondensables can adversely affect system operation.
A technician needs to pressure-test a low-pressure centrifugal chiller for
a suspected leak. Which method is preferred under EPA Type III study
guidance?
A) Introduce oxygen into the system
B) Use hot water or a built-in system heating/pressurization device
C) Pressurize the system with refrigerant and vent it afterward
D) Use compressed air at any pressure
✓✓ Correct Answer: B) Use hot water or a built-in system
heating/pressurization device
Rationale: EPA Type III test topics identify the hot water method or
a built-in system heating/pressurization device as the preferred method
for leak-test pressurization of low-pressure systems. Controlled heating
raises refrigerant pressure without introducing a foreign gas into the
system. Nitrogen is another recognized method when appropriate.
Oxygen must never be used for pressure testing because it creates a
serious combustion hazard in refrigeration systems. The technician must
also follow the equipment manufacturer's procedures and ensure that
the test pressure remains within the permitted limits.
3|Page
, EPA 608 TYPE III CERTIFICATION EXAM
A technician is performing a leak test on a low-pressure centrifugal
chiller. Which substance should never be used to pressurize the system?
A) Nitrogen
B) Hot water
C) Oxygen
D) Refrigerant vapor, where permitted by the procedure
✓✓ Correct Answer: C) Oxygen
Rationale: Oxygen should never be introduced into a refrigeration
system for pressure testing. Oxygen can react dangerously with oils and
other materials, creating a significant fire or explosion hazard. Nitrogen
is commonly used for pressure testing when permitted and when the
correct procedures are followed. Hot water is also identified in EPA Type
III study material as a preferred method for certain low-pressure
systems. The technician must distinguish between safe pressure-testing
methods and dangerous practices that can compromise equipment and
personal safety.
Recovery and evacuation
A technician is recovering refrigerant from a low-pressure centrifugal
chiller before opening the system for a major repair. Which action best
supports efficient recovery?
A) Recover only vapor and leave liquid refrigerant in the system
B) Recover liquid refrigerant at the beginning of the recovery process
when practical
C) Add oxygen to speed up recovery
D) Open the system before recovery begins
4|Page
EPA 608 TYPE III CERTIFICATION EXAM STUDY
GUIDE: LOW-PRESSURE REFRIGERATION
SYSTEMS, CE, 2026/2027
A technician is preparing to service a large centrifugal chiller containing
R-123. The technician needs to open the refrigerant circuit for a major
repair. Which certification is specifically intended for servicing this type
of low-pressure appliance?
A) Type I
B) Type II
C) Type III
D) Type V
✓✓ Correct Answer: C) Type III
Rationale: EPA Section 608 Type III certification is intended for
technicians who service or dispose of low-pressure appliances.
Centrifugal chillers are a key example of equipment associated with
low-pressure refrigeration. Type I certification covers small appliances,
while Type II covers high- and very high-pressure appliances other than
small appliances and MVACs. Universal certification covers all
equipment categories. A technician must hold the appropriate
certification for the work being performed, and an EPA-approved
certification examination is required.
A technician measures the pressure in a centrifugal chiller and finds that
the system is operating below atmospheric pressure. Which condition is
most likely to occur if the system develops a leak?
A) Refrigerant automatically escapes rapidly into the atmosphere
1|Page
, EPA 608 TYPE III CERTIFICATION EXAM
B) Air and moisture may enter the system
C) The compressor immediately stops because of high discharge
pressure
D) The condenser pressure increases above atmospheric pressure
✓✓ Correct Answer: B) Air and moisture may enter the system
Rationale: Low-pressure refrigeration systems often operate below
atmospheric pressure on the evaporator side. When the pressure inside
the system is lower than the surrounding atmospheric pressure, a leak
can allow air and moisture to enter the system rather than refrigerant
escaping outward. Noncondensable gases can interfere with heat
transfer and raise condensing pressure, while moisture can contribute
to corrosion, freezing, and other system problems. This is why leak
detection and proper evacuation are important when servicing low-
pressure chillers. The technician should not assume that a low-pressure
system is leak-free simply because refrigerant is not visibly escaping.
A centrifugal chiller is suspected of leaking because the purge unit is
operating much more frequently than usual. What should the
technician recognize?
A) Excessive purge operation may indicate air or other noncondensables
entering the system
B) The purge unit proves that the compressor has failed
C) Frequent purge operation always indicates an overcharged system
D) The purge unit eliminates the need for leak testing
✓✓ Correct Answer: A) Excessive purge operation may indicate air or
other noncondensables entering the system
2|Page
, EPA 608 TYPE III CERTIFICATION EXAM
Rationale: A purge unit removes noncondensable gases, such as air,
from certain low-pressure refrigeration systems. Because low-pressure
chillers can draw air inward through leaks, an increase in purge activity
may be a warning sign of leakage or another source of
noncondensables. However, excessive purge operation does not prove a
particular leak location or cause. The technician should investigate the
system using appropriate leak-detection methods and evaluate purge
performance. Purging is not a substitute for repairing leaks, and the
presence of noncondensables can adversely affect system operation.
A technician needs to pressure-test a low-pressure centrifugal chiller for
a suspected leak. Which method is preferred under EPA Type III study
guidance?
A) Introduce oxygen into the system
B) Use hot water or a built-in system heating/pressurization device
C) Pressurize the system with refrigerant and vent it afterward
D) Use compressed air at any pressure
✓✓ Correct Answer: B) Use hot water or a built-in system
heating/pressurization device
Rationale: EPA Type III test topics identify the hot water method or
a built-in system heating/pressurization device as the preferred method
for leak-test pressurization of low-pressure systems. Controlled heating
raises refrigerant pressure without introducing a foreign gas into the
system. Nitrogen is another recognized method when appropriate.
Oxygen must never be used for pressure testing because it creates a
serious combustion hazard in refrigeration systems. The technician must
also follow the equipment manufacturer's procedures and ensure that
the test pressure remains within the permitted limits.
3|Page
, EPA 608 TYPE III CERTIFICATION EXAM
A technician is performing a leak test on a low-pressure centrifugal
chiller. Which substance should never be used to pressurize the system?
A) Nitrogen
B) Hot water
C) Oxygen
D) Refrigerant vapor, where permitted by the procedure
✓✓ Correct Answer: C) Oxygen
Rationale: Oxygen should never be introduced into a refrigeration
system for pressure testing. Oxygen can react dangerously with oils and
other materials, creating a significant fire or explosion hazard. Nitrogen
is commonly used for pressure testing when permitted and when the
correct procedures are followed. Hot water is also identified in EPA Type
III study material as a preferred method for certain low-pressure
systems. The technician must distinguish between safe pressure-testing
methods and dangerous practices that can compromise equipment and
personal safety.
Recovery and evacuation
A technician is recovering refrigerant from a low-pressure centrifugal
chiller before opening the system for a major repair. Which action best
supports efficient recovery?
A) Recover only vapor and leave liquid refrigerant in the system
B) Recover liquid refrigerant at the beginning of the recovery process
when practical
C) Add oxygen to speed up recovery
D) Open the system before recovery begins
4|Page
