NATE A/C Exam #1 Test Questions and Answers Graded A
Low airflow over a residential split system air
conditioning evaporator can cause An oil separator must be mounted
A: Liquid flood-back to the compressor A: Level
B: A decrease in compression ratio B: Below the compressor crankcase
C: An increase in suction line superheat C: Above the compressor crankcase
D: Oil logging in the evaporator - D: In the suction line - ANSWER -A: Level
ANSWER -A: Liquid flood-back to the
compressor
Which of the following metering devices controls
evaporator pressure?
Which of the following is the correct sequence of
work? A: Thermostatic expansion valve
A: Attach gauge manifold, recover refrigerant, B: Fixed orifice
replace filter core, evacuate the system,
recharge the system. C: Low side float
B: Recover refrigerant, evacuate the system, D: None of these - ANSWER -D: None of
replace filter core, recharge the system. these
C: Attach gauge manifold, evacuate the system, An automatic expansion valve controls
replace filter core, recover refrigerant, recharge evaporator pressure.
the system.
D: Attach gauge manifold, recharge the system, The purpose of the external equalizer on a
evacuate the system, replace filter core. - thermostatic expansion valve is
ANSWER -A: Attach gauge manifold,
recover refrigerant, replace filter core, evacuate A: To equalize evaporator pressure drop with
the system, recharge the system. respect to the TEV
B: To equalize the evaporator pressure drop
As the pressure on a liquid is increased, the
vaporization temperature of the liquid C: To help prevent liquid floodback
A: Decreases D: To allow the high side pressure to equalize to
the low side when the compressor cycles off -
B: Increases ANSWER -A: To equalize evaporator
pressure drop with respect to the TEV
C: Remains unchanged
D: Varies - ANSWER -B: Increases The higher the MERV rating of a filter-drier, the
1/9
, NATE A/C Exam #1 Test Questions and Answers Graded A
A: More efficient the drier at absorbing moisture Vacuum pressures are measured in
B: Less efficient the drier at absorbing moisture A: Microns
C: Smaller the particles the filter can entrap B: Millimeters of mercury
D: MERV does not apply to filter-driers - C: Inches of mercury
ANSWER -D: MERV does not apply to
filter-driers D: All of the above - ANSWER -D: All of the
above
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 The number 25,400 relates to
passes through the filter. MERV is a standard
used to measure the overall efficiency of a filter. A: Microns/inch
Higher MERV ratings mean fewer dust particles
and other airborne contaminants pass through B: Btu/ton
the filter. Filters with a merv rating of 9 to 12 are
used in commercial and industrial applications C: Cfm/hp
and will stop particles in the 1 to 3 micron range.
These filters are a great choice for home owners D: Cfm/ton - ANSWER -A: Microns/inch
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 The general rule of thumb for airflow is
recommended by the manufacturer because they
will have a negative effect on air flow when they A: 400 cfm/ton
become dirty. This can lead to performance
problems and decreased operating efficiency. B: 400 cfm/hp
The most efficient filters have merv ratings of 13
to 16 and will stop particles as small as .3 C: 6 cfm/sq
microns. These filters are used in hospitals and
other super clean environments. D: 144 cfm/cu - ANSWER -A: 400 cfm/ton
Zeolite is used with A double suction riser is used to
A: Refrigerant filter-driers A: Help improve refrigerant return
B: HEPA filters B: Allow the compressor to pump at a greater
capacity
C: Pipe threads
C: Decrease suction line resistance
D: Solder - ANSWER -A: Refrigerant filter-
driers D: Improve oil return as system capacity
changes - ANSWER -D: Improve oil return
as system capacity changes
2/9
Low airflow over a residential split system air
conditioning evaporator can cause An oil separator must be mounted
A: Liquid flood-back to the compressor A: Level
B: A decrease in compression ratio B: Below the compressor crankcase
C: An increase in suction line superheat C: Above the compressor crankcase
D: Oil logging in the evaporator - D: In the suction line - ANSWER -A: Level
ANSWER -A: Liquid flood-back to the
compressor
Which of the following metering devices controls
evaporator pressure?
Which of the following is the correct sequence of
work? A: Thermostatic expansion valve
A: Attach gauge manifold, recover refrigerant, B: Fixed orifice
replace filter core, evacuate the system,
recharge the system. C: Low side float
B: Recover refrigerant, evacuate the system, D: None of these - ANSWER -D: None of
replace filter core, recharge the system. these
C: Attach gauge manifold, evacuate the system, An automatic expansion valve controls
replace filter core, recover refrigerant, recharge evaporator pressure.
the system.
D: Attach gauge manifold, recharge the system, The purpose of the external equalizer on a
evacuate the system, replace filter core. - thermostatic expansion valve is
ANSWER -A: Attach gauge manifold,
recover refrigerant, replace filter core, evacuate A: To equalize evaporator pressure drop with
the system, recharge the system. respect to the TEV
B: To equalize the evaporator pressure drop
As the pressure on a liquid is increased, the
vaporization temperature of the liquid C: To help prevent liquid floodback
A: Decreases D: To allow the high side pressure to equalize to
the low side when the compressor cycles off -
B: Increases ANSWER -A: To equalize evaporator
pressure drop with respect to the TEV
C: Remains unchanged
D: Varies - ANSWER -B: Increases The higher the MERV rating of a filter-drier, the
1/9
, NATE A/C Exam #1 Test Questions and Answers Graded A
A: More efficient the drier at absorbing moisture Vacuum pressures are measured in
B: Less efficient the drier at absorbing moisture A: Microns
C: Smaller the particles the filter can entrap B: Millimeters of mercury
D: MERV does not apply to filter-driers - C: Inches of mercury
ANSWER -D: MERV does not apply to
filter-driers D: All of the above - ANSWER -D: All of the
above
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 The number 25,400 relates to
passes through the filter. MERV is a standard
used to measure the overall efficiency of a filter. A: Microns/inch
Higher MERV ratings mean fewer dust particles
and other airborne contaminants pass through B: Btu/ton
the filter. Filters with a merv rating of 9 to 12 are
used in commercial and industrial applications C: Cfm/hp
and will stop particles in the 1 to 3 micron range.
These filters are a great choice for home owners D: Cfm/ton - ANSWER -A: Microns/inch
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 The general rule of thumb for airflow is
recommended by the manufacturer because they
will have a negative effect on air flow when they A: 400 cfm/ton
become dirty. This can lead to performance
problems and decreased operating efficiency. B: 400 cfm/hp
The most efficient filters have merv ratings of 13
to 16 and will stop particles as small as .3 C: 6 cfm/sq
microns. These filters are used in hospitals and
other super clean environments. D: 144 cfm/cu - ANSWER -A: 400 cfm/ton
Zeolite is used with A double suction riser is used to
A: Refrigerant filter-driers A: Help improve refrigerant return
B: HEPA filters B: Allow the compressor to pump at a greater
capacity
C: Pipe threads
C: Decrease suction line resistance
D: Solder - ANSWER -A: Refrigerant filter-
driers D: Improve oil return as system capacity
changes - ANSWER -D: Improve oil return
as system capacity changes
2/9
