MACS 609 CERTIFICATION EXAM NEWEST 2026
ACTUAL EXAM| COMPLETE REAL EXAM
QUESTIONS AND CORRECT VERIFIED ANSWERS/
ALREADY GRADED A+| MACS 609 CERTIFICATION
EXAM REVIEW (MOST RECENT!!)
Which type of tank must be used during the transfer of refrigerant? -
ANSWER - Tanks marked DOT 4BA
When can HFC-134a become combustible in a mobile air conditioning
system? - ANSWER - If shop air is used in the system in an attempt to
check for leaks and HFC-134a is present
Mineral-based lubricants are used in which type of mobile A/C system? -
ANSWER - CFC-12
How much moisture is removed from a mobile A/C system during a
typical evacuation? - ANSWER - Possibly none
Mobile A/C system design changes, new service procedures and
equipment have been developed for what reason? - ANSWER - To
reduce lifetime refrigerant emissions
Why is it necessary to ensure that service port caps containing good
seals are installed? - ANSWER - To minimize refrigerant loss
pg. 1
,HFO-1234yf has been tested and found compatible with: - ANSWER -
PAG oil
To use an electronic leak detector, how much refrigerant must a system
contain? - ANSWER - About 10% to 15% of system charge
What was a key design change for HFC-134a A/C systems versus CFC-
12 A/C systems? - ANSWER - Increased condenser capacity and airflow
What transports ultraviolet dye through the A/C system? - ANSWER -
Refrigerant oil
What part of the Clean Air Act gives the EPA authority to establish
standards regarding servicing of mobile A/C? - ANSWER - Section 609
The technician's first step in A/C system service should be to: -
ANSWER - Perform a visual inspection
HFO-1234yf is classified as "A2L-mildly flammable." This means: -
ANSWER - It can ignite under certain circumstances
If a large amount of lubricant is removed from a system during
refrigerant recovery: - ANSWER - The system likely contained too
much lubricant
pg. 2
, How much time do manufacturers suggest for proper system evacuation?
- ANSWER - 30 to 45 minutes
Why are shut-off valves located within 12 inches from the "vehicle end"
of A/C service equipment hoses? - ANSWER - To minimize venting of
refrigerant
The use of ultraviolet (UV) or fluorescent dyes in an HFO-1234yf
system is: - ANSWER - Approved by some vehicle manufactures but not
by others
One effect of some refrigerant gases in the atmosphere is that they: -
ANSWER - Contribute to trapping heat
Which item is not mentioned in the SAE J2099 Standard of refrigerant
purity? - ANSWER - Sludge
When it has been determined that an A/C system has a low refrigerant
charge, what should be done? - ANSWER - Perform a leak test
procedure
Which item is not mentioned in the SAE J1991 standard of refrigerant
purity? - ANSWER - Acid
pg. 3
ACTUAL EXAM| COMPLETE REAL EXAM
QUESTIONS AND CORRECT VERIFIED ANSWERS/
ALREADY GRADED A+| MACS 609 CERTIFICATION
EXAM REVIEW (MOST RECENT!!)
Which type of tank must be used during the transfer of refrigerant? -
ANSWER - Tanks marked DOT 4BA
When can HFC-134a become combustible in a mobile air conditioning
system? - ANSWER - If shop air is used in the system in an attempt to
check for leaks and HFC-134a is present
Mineral-based lubricants are used in which type of mobile A/C system? -
ANSWER - CFC-12
How much moisture is removed from a mobile A/C system during a
typical evacuation? - ANSWER - Possibly none
Mobile A/C system design changes, new service procedures and
equipment have been developed for what reason? - ANSWER - To
reduce lifetime refrigerant emissions
Why is it necessary to ensure that service port caps containing good
seals are installed? - ANSWER - To minimize refrigerant loss
pg. 1
,HFO-1234yf has been tested and found compatible with: - ANSWER -
PAG oil
To use an electronic leak detector, how much refrigerant must a system
contain? - ANSWER - About 10% to 15% of system charge
What was a key design change for HFC-134a A/C systems versus CFC-
12 A/C systems? - ANSWER - Increased condenser capacity and airflow
What transports ultraviolet dye through the A/C system? - ANSWER -
Refrigerant oil
What part of the Clean Air Act gives the EPA authority to establish
standards regarding servicing of mobile A/C? - ANSWER - Section 609
The technician's first step in A/C system service should be to: -
ANSWER - Perform a visual inspection
HFO-1234yf is classified as "A2L-mildly flammable." This means: -
ANSWER - It can ignite under certain circumstances
If a large amount of lubricant is removed from a system during
refrigerant recovery: - ANSWER - The system likely contained too
much lubricant
pg. 2
, How much time do manufacturers suggest for proper system evacuation?
- ANSWER - 30 to 45 minutes
Why are shut-off valves located within 12 inches from the "vehicle end"
of A/C service equipment hoses? - ANSWER - To minimize venting of
refrigerant
The use of ultraviolet (UV) or fluorescent dyes in an HFO-1234yf
system is: - ANSWER - Approved by some vehicle manufactures but not
by others
One effect of some refrigerant gases in the atmosphere is that they: -
ANSWER - Contribute to trapping heat
Which item is not mentioned in the SAE J2099 Standard of refrigerant
purity? - ANSWER - Sludge
When it has been determined that an A/C system has a low refrigerant
charge, what should be done? - ANSWER - Perform a leak test
procedure
Which item is not mentioned in the SAE J1991 standard of refrigerant
purity? - ANSWER - Acid
pg. 3
