NATE A/C
NATE A/C EXAM 1 STUDY GUIDE LATEST VERSION
/QUESTIONS AND CORRECT ANSWERS A GRADE
SCORE SOLUTION 2025-2026.
Low airflow over a residential split system air conditioning evaporator can cause
A: Liquid flood-back to the compressor
B: A decrease in compression ratio
C: An increase in suction line superheat
D: Oil logging in the evaporator -Correct Answers ✔-A: Liquid flood-back to the
compressor
Which of the following is the correct sequence of work?
A: Attach gauge manifold, recover refrigerant, replace filter core, evacuate the
system, recharge the system.
B: Recover refrigerant, evacuate the system, replace filter core, recharge the
system.
C: Attach gauge manifold, evacuate the system, replace filter core, recover
refrigerant, recharge the system.
D: Attach gauge manifold, recharge the system, evacuate the system, replace filter
core. -Correct Answers ✔-A: Attach gauge manifold, recover refrigerant, replace
filter core, evacuate the system, recharge the system.
As the pressure on a liquid is increased, the vaporization temperature of the liquid
A: Decreases
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B: Increases
C: Remains unchanged
D: Varies -Correct Answers ✔-B: Increases
An oil separator must be mounted
A: Level
B: Below the compressor crankcase
C: Above the compressor crankcase
D: In the suction line -Correct Answers ✔-A: Level
Which of the following metering devices controls evaporator pressure?
A: Thermostatic expansion valve
B: Fixed orifice
C: Low side float
D: None of these -Correct Answers ✔-D: None of these
An automatic expansion valve controls evaporator pressure.
The purpose of the external equalizer on a thermostatic expansion valve is
A: To equalize evaporator pressure drop with respect to the TEV
B: To equalize the evaporator pressure drop
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C: To help prevent liquid floodback
D: To allow the high side pressure to equalize to the low side when the
compressor cycles off -Correct Answers ✔-A: To equalize evaporator pressure
drop with respect to the TEV
The higher the MERV rating of a filter-drier, the
A: More efficient the drier at absorbing moisture
B: Less efficient the drier at absorbing moisture
C: Smaller the particles the filter can entrap
D: MERV does not apply to filter-driers -Correct Answers ✔-D: MERV does not
apply to filter-driers
Minimum Efficiency Reporting Value - MERV ratings are used to rate the ability
of an air conditioning filter to remove dust from the air as it passes through the
filter. MERV is a standard used to measure the overall efficiency of a filter. Higher
MERV ratings mean fewer dust particles and other airborne contaminants pass
through the filter. Filters with a merv rating of 9 to 12 are used in commercial and
industrial applications and will stop particles in the 1 to 3 micron range. These
filters are a great choice for home owners who want the best dust control possible.
When using filters with Merv 9 ratings and above it is important to clean or replace
them when recommended by the manufacturer because they will have a negative
effect on air flow when they become dirty. This can lead to performance problems
and decreased operating efficiency. The most efficient filters have merv ratings of
13 to 16 and will stop particles as small as .3 microns. These filters are used in
hospitals and other super clean environments.
Zeolite is used with
NATE A/C
NATE A/C EXAM 1 STUDY GUIDE LATEST VERSION
/QUESTIONS AND CORRECT ANSWERS A GRADE
SCORE SOLUTION 2025-2026.
Low airflow over a residential split system air conditioning evaporator can cause
A: Liquid flood-back to the compressor
B: A decrease in compression ratio
C: An increase in suction line superheat
D: Oil logging in the evaporator -Correct Answers ✔-A: Liquid flood-back to the
compressor
Which of the following is the correct sequence of work?
A: Attach gauge manifold, recover refrigerant, replace filter core, evacuate the
system, recharge the system.
B: Recover refrigerant, evacuate the system, replace filter core, recharge the
system.
C: Attach gauge manifold, evacuate the system, replace filter core, recover
refrigerant, recharge the system.
D: Attach gauge manifold, recharge the system, evacuate the system, replace filter
core. -Correct Answers ✔-A: Attach gauge manifold, recover refrigerant, replace
filter core, evacuate the system, recharge the system.
As the pressure on a liquid is increased, the vaporization temperature of the liquid
A: Decreases
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,NATE A/C
B: Increases
C: Remains unchanged
D: Varies -Correct Answers ✔-B: Increases
An oil separator must be mounted
A: Level
B: Below the compressor crankcase
C: Above the compressor crankcase
D: In the suction line -Correct Answers ✔-A: Level
Which of the following metering devices controls evaporator pressure?
A: Thermostatic expansion valve
B: Fixed orifice
C: Low side float
D: None of these -Correct Answers ✔-D: None of these
An automatic expansion valve controls evaporator pressure.
The purpose of the external equalizer on a thermostatic expansion valve is
A: To equalize evaporator pressure drop with respect to the TEV
B: To equalize the evaporator pressure drop
NATE A/C
, NATE A/C
C: To help prevent liquid floodback
D: To allow the high side pressure to equalize to the low side when the
compressor cycles off -Correct Answers ✔-A: To equalize evaporator pressure
drop with respect to the TEV
The higher the MERV rating of a filter-drier, the
A: More efficient the drier at absorbing moisture
B: Less efficient the drier at absorbing moisture
C: Smaller the particles the filter can entrap
D: MERV does not apply to filter-driers -Correct Answers ✔-D: MERV does not
apply to filter-driers
Minimum Efficiency Reporting Value - MERV ratings are used to rate the ability
of an air conditioning filter to remove dust from the air as it passes through the
filter. MERV is a standard used to measure the overall efficiency of a filter. Higher
MERV ratings mean fewer dust particles and other airborne contaminants pass
through the filter. Filters with a merv rating of 9 to 12 are used in commercial and
industrial applications and will stop particles in the 1 to 3 micron range. These
filters are a great choice for home owners who want the best dust control possible.
When using filters with Merv 9 ratings and above it is important to clean or replace
them when recommended by the manufacturer because they will have a negative
effect on air flow when they become dirty. This can lead to performance problems
and decreased operating efficiency. The most efficient filters have merv ratings of
13 to 16 and will stop particles as small as .3 microns. These filters are used in
hospitals and other super clean environments.
Zeolite is used with
NATE A/C
