EPA 608 TYPE III – COMPREHENSIVE EXAM PREP - Section
608 Low-Pressure Appliance Certification Practice Test Bank
2026
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. A low-pressure chiller is suspected of having a leak in the evaporator tube
bundle. What is the safest and most effective method to locate the leak without
overpressurizing the system?
A. Pressurize the system to 25 psig with nitrogen and use an electronic leak detector
B. Drain the water side, pressurize the refrigerant side to no more than 10 psig with
nitrogen or heat the refrigerant to raise pressure, and place a leak detector probe
at the water box drain
C. Isolate the evaporator and pressurize it to 50 psig with nitrogen
D. Add fluorescent dye and run the chiller for 24 hours
Rationale: The maximum safe test pressure for a low-pressure chiller is 10 psig. To check
the evaporator tubes, drain the water side, warm the refrigerant to increase pressure, and
place a detector at the drain port. Exceeding 10 psig can rupture the safety disc (set at 15
psig) .
2. What is the approximate boiling point of R-123 at atmospheric pressure (14.7
psia)?
A. -14.9°F
B. 32°F
C. 82°F
D. 118°F
,Rationale: R-123 boils at approximately 82°F at atmospheric pressure. This high boiling
point is why R-123 operates below atmospheric pressure at normal chiller temperatures
(35-45°F) .
3. According to ASHRAE Standard 34, what safety classification does R-123 have,
and what requirement does this classification trigger?
A. A1 – requires no special monitoring
B. B1 – requires equipment room refrigerant detectors, alarms, and ventilation
C. A2L – requires explosion-proof electrical equipment
D. B2 – requires full hazmat suits
Rationale: R-123 is classified as B1. The "B" indicates higher toxicity (effects below 400
ppm), and "1" means no flammability. This triggers ASHRAE Standard 15 requirements for
machinery rooms, including refrigerant detectors, alarms, ventilation, and emergency
shutdown protocols .
4. A Type III technician discovers a low-pressure chiller containing 200 pounds of
R-123 with an annual leak rate of 15%. The system is used for comfort cooling.
Under EPA regulations, what action is required?
A. No action is required because the leak rate is below 30%
B. The leak must be repaired within 30 days
C. The chiller must be retrofitted or retired immediately
D. A leak inspection record must be created but no repair is required
Rationale: Comfort cooling systems have a leak rate threshold of 10% annually. A 15%
leak rate exceeds this threshold. The EPA requires repair within 30 days of discovery. The
18-month retrofit/retirement deadline applies only if the system cannot be repaired .
,5. What is the minimum evacuation level required for a low-pressure system being
opened for major repair when using a recovery machine manufactured AFTER
November 15, 1993?
A. 0 psig
B. 15 inches Hg vacuum
C. 25 inches Hg vacuum
D. 25 mm Hg absolute
Rationale: Recovery machines manufactured after November 15, 1993, must evacuate
low-pressure appliances to 25 mm Hg absolute before major repairs. Pre-1993 machines
require 25 inches Hg vacuum .
6. A 350-ton R-11 chiller has been pumped down to 0 psig, and all liquid
refrigerant has been recovered. According to EPA estimates, approximately how
much refrigerant vapor remains in the system?
A. 10 pounds
B. 20 pounds
C. 100 pounds
D. 500 pounds
Rationale: The EPA estimates approximately 100 pounds of refrigerant vapor remains in
an average 350-ton R-11 chiller at 0 psig after liquid recovery .
7. What is the maximum allowable test pressure for leak testing a low-pressure
centrifugal chiller with nitrogen?
A. 5 psig
B. 10 psig
C. 15 psig
D. 20 psig
Rationale: The maximum test pressure for leak testing a low-pressure chiller is 10 psig.
Pressurizing above this limit risks bursting the rupture disc, which is set to relieve at 15
psig .
, 8. A technician is using a recovery machine manufactured BEFORE November 15,
1993, to evacuate a low-pressure appliance. What vacuum level must be achieved
before making a major repair?
A. 0 psig
B. 15 inches Hg vacuum
C. 25 inches Hg vacuum
D. 25 mm Hg absolute
Rationale: Recovery machines manufactured before November 15, 1993, must evacuate
low-pressure appliances to 25 inches Hg vacuum .
9. Excessive running of the purge unit on a low-pressure chiller generally indicates
which problem?
A. The ambient temperature is too high
B. The air sensors are faulty
C. The system is leaking
D. The efficiency of the purge unit is too low
Rationale: Excessive purge unit operation indicates air is entering the system, which means
there is a leak. The purge unit removes non-condensables (air) from the system; if it runs
excessively, it is trying to remove air that is continuously entering through a leak .
10. According to ASHRAE Guideline 3-1996, if the pressure in a system rises from 1
mm Hg to what level during a standing vacuum test, should the system be
checked for leaks?
A. 1.5 mm Hg
B. 2.0 mm Hg
C. 2.5 mm Hg
D. 3.0 mm Hg
608 Low-Pressure Appliance Certification Practice Test Bank
2026
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. A low-pressure chiller is suspected of having a leak in the evaporator tube
bundle. What is the safest and most effective method to locate the leak without
overpressurizing the system?
A. Pressurize the system to 25 psig with nitrogen and use an electronic leak detector
B. Drain the water side, pressurize the refrigerant side to no more than 10 psig with
nitrogen or heat the refrigerant to raise pressure, and place a leak detector probe
at the water box drain
C. Isolate the evaporator and pressurize it to 50 psig with nitrogen
D. Add fluorescent dye and run the chiller for 24 hours
Rationale: The maximum safe test pressure for a low-pressure chiller is 10 psig. To check
the evaporator tubes, drain the water side, warm the refrigerant to increase pressure, and
place a detector at the drain port. Exceeding 10 psig can rupture the safety disc (set at 15
psig) .
2. What is the approximate boiling point of R-123 at atmospheric pressure (14.7
psia)?
A. -14.9°F
B. 32°F
C. 82°F
D. 118°F
,Rationale: R-123 boils at approximately 82°F at atmospheric pressure. This high boiling
point is why R-123 operates below atmospheric pressure at normal chiller temperatures
(35-45°F) .
3. According to ASHRAE Standard 34, what safety classification does R-123 have,
and what requirement does this classification trigger?
A. A1 – requires no special monitoring
B. B1 – requires equipment room refrigerant detectors, alarms, and ventilation
C. A2L – requires explosion-proof electrical equipment
D. B2 – requires full hazmat suits
Rationale: R-123 is classified as B1. The "B" indicates higher toxicity (effects below 400
ppm), and "1" means no flammability. This triggers ASHRAE Standard 15 requirements for
machinery rooms, including refrigerant detectors, alarms, ventilation, and emergency
shutdown protocols .
4. A Type III technician discovers a low-pressure chiller containing 200 pounds of
R-123 with an annual leak rate of 15%. The system is used for comfort cooling.
Under EPA regulations, what action is required?
A. No action is required because the leak rate is below 30%
B. The leak must be repaired within 30 days
C. The chiller must be retrofitted or retired immediately
D. A leak inspection record must be created but no repair is required
Rationale: Comfort cooling systems have a leak rate threshold of 10% annually. A 15%
leak rate exceeds this threshold. The EPA requires repair within 30 days of discovery. The
18-month retrofit/retirement deadline applies only if the system cannot be repaired .
,5. What is the minimum evacuation level required for a low-pressure system being
opened for major repair when using a recovery machine manufactured AFTER
November 15, 1993?
A. 0 psig
B. 15 inches Hg vacuum
C. 25 inches Hg vacuum
D. 25 mm Hg absolute
Rationale: Recovery machines manufactured after November 15, 1993, must evacuate
low-pressure appliances to 25 mm Hg absolute before major repairs. Pre-1993 machines
require 25 inches Hg vacuum .
6. A 350-ton R-11 chiller has been pumped down to 0 psig, and all liquid
refrigerant has been recovered. According to EPA estimates, approximately how
much refrigerant vapor remains in the system?
A. 10 pounds
B. 20 pounds
C. 100 pounds
D. 500 pounds
Rationale: The EPA estimates approximately 100 pounds of refrigerant vapor remains in
an average 350-ton R-11 chiller at 0 psig after liquid recovery .
7. What is the maximum allowable test pressure for leak testing a low-pressure
centrifugal chiller with nitrogen?
A. 5 psig
B. 10 psig
C. 15 psig
D. 20 psig
Rationale: The maximum test pressure for leak testing a low-pressure chiller is 10 psig.
Pressurizing above this limit risks bursting the rupture disc, which is set to relieve at 15
psig .
, 8. A technician is using a recovery machine manufactured BEFORE November 15,
1993, to evacuate a low-pressure appliance. What vacuum level must be achieved
before making a major repair?
A. 0 psig
B. 15 inches Hg vacuum
C. 25 inches Hg vacuum
D. 25 mm Hg absolute
Rationale: Recovery machines manufactured before November 15, 1993, must evacuate
low-pressure appliances to 25 inches Hg vacuum .
9. Excessive running of the purge unit on a low-pressure chiller generally indicates
which problem?
A. The ambient temperature is too high
B. The air sensors are faulty
C. The system is leaking
D. The efficiency of the purge unit is too low
Rationale: Excessive purge unit operation indicates air is entering the system, which means
there is a leak. The purge unit removes non-condensables (air) from the system; if it runs
excessively, it is trying to remove air that is continuously entering through a leak .
10. According to ASHRAE Guideline 3-1996, if the pressure in a system rises from 1
mm Hg to what level during a standing vacuum test, should the system be
checked for leaks?
A. 1.5 mm Hg
B. 2.0 mm Hg
C. 2.5 mm Hg
D. 3.0 mm Hg
