EPA SECTION 608 TYPE III CERTIFICATION
PRACTICE EXAM STUDY GUIDE UPDATED
2026/2027 | VERIFIED QUESTIONS AND ANSWERS
WITH DETAILED RATIONALES | LOW PRESSURE
REFRIGERATION SYSTEMS CHILLERS EXAM PREP
EPA SECTION 608 TYPE III CERTIFICATION PRACTICE EXAM
LOW PRESSURE REFRIGERATION SYSTEMS & CHILLERS — 2026/2027 EDITION
• 200 verified practice questions covering all Type III exam topics with A–E
multiple choice options, highlighted correct answers, and detailed EXPERT
RATIONALE to reinforce understanding.
• Study tip: Work through each question independently before checking the
answer, then read the EXPERT RATIONALE carefully — this material is best
absorbed by understanding why, not just what.
1. What type of refrigerant is most commonly used in low-pressure centrifugal
chiller systems?
A. R-22
B. R-410A
C. R-134a
D. R-123
E. R-502
Correct Answer: D. R-123
EXPERT RATIONALE: R-123 is the refrigerant of choice for low-pressure centrifugal
chillers, replacing R-11. It operates at pressures below atmospheric pressure (in a
vacuum) during normal operation, which is characteristic of low-pressure systems.
,2. Low-pressure refrigeration systems typically operate the evaporator at
pressures:
A. Above 100 psig
B. Between 50 and 100 psig
C. Between 15 and 50 psig
D. Below atmospheric pressure (in a vacuum)
E. Exactly at atmospheric pressure
Correct Answer: D. Below atmospheric pressure (in a vacuum)
EXPERT RATIONALE: Low-pressure refrigerants like R-123 and R-11 boil at
temperatures above their atmospheric boiling points during chiller operation, meaning
evaporator pressure is below 0 psig — operating in a vacuum. This is a defining
characteristic of Type III systems.
3. What is the boiling point of R-123 at atmospheric pressure?
A. -41.4°F
B. 14°F
C. 32°F
D. 82.2°F
E. 100°F
Correct Answer: D. 82.2°F
EXPERT RATIONALE: R-123 has an atmospheric boiling point of approximately
82.2°F. Because typical chiller evaporator temperatures are below this point, the
refrigerant operates under vacuum conditions — below atmospheric pressure.
4. What is the primary hazard associated with low-pressure chiller systems
operating in a vacuum?
,A. Explosion from high internal pressure
B. Refrigerant discharge from relief valves
C. Air and moisture infiltration into the system
D. Compressor surge at high pressure
E. Overcharge of refrigerant
Correct Answer: C. Air and moisture infiltration into the system
EXPERT RATIONALE: Because low-pressure systems operate below atmospheric
pressure, any leak allows air and moisture to enter rather than refrigerant to escape.
This leads to elevated head pressure, reduced efficiency, and acid formation within the
system.
5. Which of the following best describes a centrifugal compressor used in low-
pressure chillers?
A. Positive displacement, uses pistons
B. Positive displacement, uses rotors
C. Dynamic, uses screws
D. Dynamic, uses an impeller to accelerate refrigerant
E. Positive displacement, uses vanes
Correct Answer: D. Dynamic, uses an impeller to accelerate refrigerant
EXPERT RATIONALE: Centrifugal compressors are dynamic (kinetic) machines that
use a rotating impeller to impart velocity to the refrigerant vapor. The velocity is then
converted to pressure in the diffuser section. This is different from positive displacement
compressors like reciprocating or screw types.
6. The EPA Section 608 regulations require that recovery equipment used on
low-pressure systems achieve what level of evacuation before opening or
disposing of the system?
, A. 0 psig
B. 10 inches Hg vacuum
C. 25 inches Hg vacuum
D. 29.9 inches Hg vacuum
E. 15 psig
Correct Answer: C. 25 inches Hg vacuum
EXPERT RATIONALE: EPA regulations under Section 608 require that low-pressure
systems be evacuated to 25 inches of mercury vacuum before the system is opened for
major repairs or disposal. This minimizes refrigerant release into the atmosphere.
7. Which refrigerant was the original refrigerant used in large centrifugal low-
pressure chillers before being phased out?
A. R-11
B. R-12
C. R-22
D. R-502
E. R-123
Correct Answer: A. R-11
EXPERT RATIONALE: R-11 (trichlorofluoromethane) was the dominant refrigerant in
large low-pressure centrifugal chillers for decades. It was phased out under the Montreal
Protocol due to its very high ozone depletion potential (ODP of 1.0). R-123 is its primary
replacement.
8. What device on a low-pressure chiller is specifically designed to prevent
dangerously high vacuum conditions?
A. High-pressure cut-out switch
PRACTICE EXAM STUDY GUIDE UPDATED
2026/2027 | VERIFIED QUESTIONS AND ANSWERS
WITH DETAILED RATIONALES | LOW PRESSURE
REFRIGERATION SYSTEMS CHILLERS EXAM PREP
EPA SECTION 608 TYPE III CERTIFICATION PRACTICE EXAM
LOW PRESSURE REFRIGERATION SYSTEMS & CHILLERS — 2026/2027 EDITION
• 200 verified practice questions covering all Type III exam topics with A–E
multiple choice options, highlighted correct answers, and detailed EXPERT
RATIONALE to reinforce understanding.
• Study tip: Work through each question independently before checking the
answer, then read the EXPERT RATIONALE carefully — this material is best
absorbed by understanding why, not just what.
1. What type of refrigerant is most commonly used in low-pressure centrifugal
chiller systems?
A. R-22
B. R-410A
C. R-134a
D. R-123
E. R-502
Correct Answer: D. R-123
EXPERT RATIONALE: R-123 is the refrigerant of choice for low-pressure centrifugal
chillers, replacing R-11. It operates at pressures below atmospheric pressure (in a
vacuum) during normal operation, which is characteristic of low-pressure systems.
,2. Low-pressure refrigeration systems typically operate the evaporator at
pressures:
A. Above 100 psig
B. Between 50 and 100 psig
C. Between 15 and 50 psig
D. Below atmospheric pressure (in a vacuum)
E. Exactly at atmospheric pressure
Correct Answer: D. Below atmospheric pressure (in a vacuum)
EXPERT RATIONALE: Low-pressure refrigerants like R-123 and R-11 boil at
temperatures above their atmospheric boiling points during chiller operation, meaning
evaporator pressure is below 0 psig — operating in a vacuum. This is a defining
characteristic of Type III systems.
3. What is the boiling point of R-123 at atmospheric pressure?
A. -41.4°F
B. 14°F
C. 32°F
D. 82.2°F
E. 100°F
Correct Answer: D. 82.2°F
EXPERT RATIONALE: R-123 has an atmospheric boiling point of approximately
82.2°F. Because typical chiller evaporator temperatures are below this point, the
refrigerant operates under vacuum conditions — below atmospheric pressure.
4. What is the primary hazard associated with low-pressure chiller systems
operating in a vacuum?
,A. Explosion from high internal pressure
B. Refrigerant discharge from relief valves
C. Air and moisture infiltration into the system
D. Compressor surge at high pressure
E. Overcharge of refrigerant
Correct Answer: C. Air and moisture infiltration into the system
EXPERT RATIONALE: Because low-pressure systems operate below atmospheric
pressure, any leak allows air and moisture to enter rather than refrigerant to escape.
This leads to elevated head pressure, reduced efficiency, and acid formation within the
system.
5. Which of the following best describes a centrifugal compressor used in low-
pressure chillers?
A. Positive displacement, uses pistons
B. Positive displacement, uses rotors
C. Dynamic, uses screws
D. Dynamic, uses an impeller to accelerate refrigerant
E. Positive displacement, uses vanes
Correct Answer: D. Dynamic, uses an impeller to accelerate refrigerant
EXPERT RATIONALE: Centrifugal compressors are dynamic (kinetic) machines that
use a rotating impeller to impart velocity to the refrigerant vapor. The velocity is then
converted to pressure in the diffuser section. This is different from positive displacement
compressors like reciprocating or screw types.
6. The EPA Section 608 regulations require that recovery equipment used on
low-pressure systems achieve what level of evacuation before opening or
disposing of the system?
, A. 0 psig
B. 10 inches Hg vacuum
C. 25 inches Hg vacuum
D. 29.9 inches Hg vacuum
E. 15 psig
Correct Answer: C. 25 inches Hg vacuum
EXPERT RATIONALE: EPA regulations under Section 608 require that low-pressure
systems be evacuated to 25 inches of mercury vacuum before the system is opened for
major repairs or disposal. This minimizes refrigerant release into the atmosphere.
7. Which refrigerant was the original refrigerant used in large centrifugal low-
pressure chillers before being phased out?
A. R-11
B. R-12
C. R-22
D. R-502
E. R-123
Correct Answer: A. R-11
EXPERT RATIONALE: R-11 (trichlorofluoromethane) was the dominant refrigerant in
large low-pressure centrifugal chillers for decades. It was phased out under the Montreal
Protocol due to its very high ozone depletion potential (ODP of 1.0). R-123 is its primary
replacement.
8. What device on a low-pressure chiller is specifically designed to prevent
dangerously high vacuum conditions?
A. High-pressure cut-out switch
