MACS 609 CERTIFICATION EXAM PREP |
Verified Questions & Correct Answers |
Automotive A/C System Service & Refrigerant
Handling Study Guide (A+ Rated)
MACS 609 CERTIFICATION EXAM PREP
Automotive A/C System Service & Refrigerant Handling
Verified Questions & CORRECT ANSWER | A+ Rated Study Guide
SECTION 1: REFRIGERANT TYPES & IDENTIFICATION
1. Which refrigerant was the primary refrigerant used in automotive air
conditioning systems before 1994?
A. R-134a
B. R-410A
C. R-22
D. R-12
E. R-1234yf
CORRECT ANSWER: D. R-12
RATIONALE: R-12 (dichlorodifluoromethane), a chlorofluorocarbon (CFC), was
the standard refrigerant in automotive A/C systems for decades. Its production was
phased out under the Montreal Protocol due to its high ozone-depleting potential (ODP
of 1.0). Starting with 1994 model year vehicles, manufacturers transitioned to R-134a.
2. What refrigerant replaced R-12 in most automotive A/C systems beginning with
the 1994 model year?
A. R-22
B. R-410A
C. R-502
D. R-1234yf
, E. R-134a
CORRECT ANSWER: E. R-134a
RATIONALE: R-134a (tetrafluoroethane), a hydrofluorocarbon (HFC), was
adopted as the replacement for R-12 in automotive systems. It has zero ozone-
depleting potential (ODP = 0) and was mandated in all new vehicles in the United States
beginning with model year 1994.
3. What is the Global Warming Potential (GWP) of R-134a?
A. 0
B. 675
C. 1,430
D. 10,900
E. 2,088
CORRECT ANSWER: C. 1,430
RATIONALE: R-134a has a Global Warming Potential (GWP) of 1,430, meaning it
is 1,430 times more potent than CO₂ as a greenhouse gas over a 100-year period. This
high GWP is the primary reason the automotive industry began transitioning to the
lower-GWP refrigerant R-1234yf.
4. What is the GWP of the refrigerant R-1234yf?
A. 1,430
B. 10,900
C. 675
D. 4
E. 0
CORRECT ANSWER: D. 4
RATIONALE: R-1234yf (2,3,3,3-tetrafluoropropene) is a hydrofluoroolefin (HFO)
with an extremely low GWP of approximately 4. This makes it nearly 358 times less
damaging to the climate than R-134a, which is why it has become the preferred
,refrigerant in new vehicle A/C systems in the European Union and increasingly in the
United States.
5. Which chemical classification does R-12 belong to?
A. Hydrofluorocarbon (HFC)
B. Hydrofluoroolefin (HFO)
C. Hydrochlorofluorocarbon (HCFC)
D. Chlorofluorocarbon (CFC)
E. Natural refrigerant
CORRECT ANSWER: D. Chlorofluorocarbon (CFC)
RATIONALE: R-12 is classified as a chlorofluorocarbon (CFC). CFCs contain
chlorine, fluorine, and carbon atoms, and the chlorine atoms are responsible for
catalytic ozone destruction in the stratosphere. The production of CFCs was banned in
developed nations under the Montreal Protocol.
6. Which refrigerant class does R-134a belong to?
A. CFC
B. HFO
C. HCFC
D. Natural
E. HFC
CORRECT ANSWER: E. HFC
RATIONALE: R-134a is a hydrofluorocarbon (HFC). HFCs contain hydrogen,
fluorine, and carbon but no chlorine, giving them zero ozone-depleting potential.
However, HFCs are potent greenhouse gases, which has driven the transition to lower-
GWP alternatives like HFOs.
7. What is the standard color code for R-134a refrigerant cylinders?
A. White
, B. Green
C. Pink/Rose
D. Orange
E. Light Blue
CORRECT ANSWER: E. Light Blue
RATIONALE: Per ASHRAE Standard 34, R-134a cylinders are color-coded light
blue. This color coding helps technicians quickly identify refrigerant types and avoid
mixing. R-12 cylinders were white, R-22 is green, R-410A is pink/rose, and R-1234yf
uses a specific blue-green color.
8. What color code is assigned to R-12 refrigerant cylinders?
A. Light Blue
B. Green
C. White
D. Yellow
E. Orange
CORRECT ANSWER: C. White
RATIONALE: R-12 cylinders are color-coded white per ASHRAE Standard 34.
Since R-12 is no longer produced in the US for automotive use, these cylinders are
primarily encountered during recovery operations on older vehicles. Knowing the color
code helps prevent confusion with other refrigerants.
9. What color are refrigerant recovery cylinders for mixed or unknown
refrigerants?
A. Red body with white collar
B. Gray body with yellow collar
C. Blue body with white collar
D. Yellow body with green collar
E. White body with gray collar
Verified Questions & Correct Answers |
Automotive A/C System Service & Refrigerant
Handling Study Guide (A+ Rated)
MACS 609 CERTIFICATION EXAM PREP
Automotive A/C System Service & Refrigerant Handling
Verified Questions & CORRECT ANSWER | A+ Rated Study Guide
SECTION 1: REFRIGERANT TYPES & IDENTIFICATION
1. Which refrigerant was the primary refrigerant used in automotive air
conditioning systems before 1994?
A. R-134a
B. R-410A
C. R-22
D. R-12
E. R-1234yf
CORRECT ANSWER: D. R-12
RATIONALE: R-12 (dichlorodifluoromethane), a chlorofluorocarbon (CFC), was
the standard refrigerant in automotive A/C systems for decades. Its production was
phased out under the Montreal Protocol due to its high ozone-depleting potential (ODP
of 1.0). Starting with 1994 model year vehicles, manufacturers transitioned to R-134a.
2. What refrigerant replaced R-12 in most automotive A/C systems beginning with
the 1994 model year?
A. R-22
B. R-410A
C. R-502
D. R-1234yf
, E. R-134a
CORRECT ANSWER: E. R-134a
RATIONALE: R-134a (tetrafluoroethane), a hydrofluorocarbon (HFC), was
adopted as the replacement for R-12 in automotive systems. It has zero ozone-
depleting potential (ODP = 0) and was mandated in all new vehicles in the United States
beginning with model year 1994.
3. What is the Global Warming Potential (GWP) of R-134a?
A. 0
B. 675
C. 1,430
D. 10,900
E. 2,088
CORRECT ANSWER: C. 1,430
RATIONALE: R-134a has a Global Warming Potential (GWP) of 1,430, meaning it
is 1,430 times more potent than CO₂ as a greenhouse gas over a 100-year period. This
high GWP is the primary reason the automotive industry began transitioning to the
lower-GWP refrigerant R-1234yf.
4. What is the GWP of the refrigerant R-1234yf?
A. 1,430
B. 10,900
C. 675
D. 4
E. 0
CORRECT ANSWER: D. 4
RATIONALE: R-1234yf (2,3,3,3-tetrafluoropropene) is a hydrofluoroolefin (HFO)
with an extremely low GWP of approximately 4. This makes it nearly 358 times less
damaging to the climate than R-134a, which is why it has become the preferred
,refrigerant in new vehicle A/C systems in the European Union and increasingly in the
United States.
5. Which chemical classification does R-12 belong to?
A. Hydrofluorocarbon (HFC)
B. Hydrofluoroolefin (HFO)
C. Hydrochlorofluorocarbon (HCFC)
D. Chlorofluorocarbon (CFC)
E. Natural refrigerant
CORRECT ANSWER: D. Chlorofluorocarbon (CFC)
RATIONALE: R-12 is classified as a chlorofluorocarbon (CFC). CFCs contain
chlorine, fluorine, and carbon atoms, and the chlorine atoms are responsible for
catalytic ozone destruction in the stratosphere. The production of CFCs was banned in
developed nations under the Montreal Protocol.
6. Which refrigerant class does R-134a belong to?
A. CFC
B. HFO
C. HCFC
D. Natural
E. HFC
CORRECT ANSWER: E. HFC
RATIONALE: R-134a is a hydrofluorocarbon (HFC). HFCs contain hydrogen,
fluorine, and carbon but no chlorine, giving them zero ozone-depleting potential.
However, HFCs are potent greenhouse gases, which has driven the transition to lower-
GWP alternatives like HFOs.
7. What is the standard color code for R-134a refrigerant cylinders?
A. White
, B. Green
C. Pink/Rose
D. Orange
E. Light Blue
CORRECT ANSWER: E. Light Blue
RATIONALE: Per ASHRAE Standard 34, R-134a cylinders are color-coded light
blue. This color coding helps technicians quickly identify refrigerant types and avoid
mixing. R-12 cylinders were white, R-22 is green, R-410A is pink/rose, and R-1234yf
uses a specific blue-green color.
8. What color code is assigned to R-12 refrigerant cylinders?
A. Light Blue
B. Green
C. White
D. Yellow
E. Orange
CORRECT ANSWER: C. White
RATIONALE: R-12 cylinders are color-coded white per ASHRAE Standard 34.
Since R-12 is no longer produced in the US for automotive use, these cylinders are
primarily encountered during recovery operations on older vehicles. Knowing the color
code helps prevent confusion with other refrigerants.
9. What color are refrigerant recovery cylinders for mixed or unknown
refrigerants?
A. Red body with white collar
B. Gray body with yellow collar
C. Blue body with white collar
D. Yellow body with green collar
E. White body with gray collar
