NATE A/C Exam #1 questions and answers
2026\2027 A+ Grade
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 answer 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 answer 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
B: Increases
C: Remains unchanged
D: Varies
- correct answer 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 answer 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 answer 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
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 answer 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 answer 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
2026\2027 A+ Grade
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 answer 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 answer 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
B: Increases
C: Remains unchanged
D: Varies
- correct answer 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 answer 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 answer 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
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 answer 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 answer 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
