NATE A/C Exam #1 Questions with All
Correct Answers 2025-2026 Updated.
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 - 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. -
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
,An oil separator must be mounted
A: Level
B: Below the compressor crankcase
C: Above the compressor crankcase
D: In the suction line - 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 - 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
, 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 - 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 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
A: Refrigerant filter-driers
B: HEPA filters
C: Pipe threads
D: Solder - Answer A: Refrigerant filter-driers
Vacuum pressures are measured in
A: Microns
Correct Answers 2025-2026 Updated.
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 - 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. -
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
,An oil separator must be mounted
A: Level
B: Below the compressor crankcase
C: Above the compressor crankcase
D: In the suction line - 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 - 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
, 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 - 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 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
A: Refrigerant filter-driers
B: HEPA filters
C: Pipe threads
D: Solder - Answer A: Refrigerant filter-driers
Vacuum pressures are measured in
A: Microns
