2. NATE Industry Competency Exam: Air
conditioning
After a vacuum pump has been used, a continuous pressure rise in the
system
likely most
indicates
the:
a. Presence of
moisture.
b. Existence of a
leak.
c. Presence of residual
refrigerant.
d. Presence of non-condensable gasses. correct
answers B
After a vacuum has been pulled to 500 microns, a pressure rise in a system,
followed
a levelingbyoff at 1500 microns, most likely
indicates the:
a. Existence of a
leak.
b. Presence of
moisture.
c. Existence of a good
vacuum.
d. Presence of non-condensable gases. correct
answers B
On initial start-up of an air conditioning system, the temperature drop
measured
the across
evaporator coil exceeds manufacturer's specifications. this condition
most likely
indicates
a/an:
a. Excessive
airflow.
b. Insufficient
c. Lack of refrigerant
airflow.
charge.
d. Refrigerant overcharge. correct
answers B
The technician is on a spring maintenance check of an air
conditioning system.
They find the
• Head pressure is higher than
following:
• Suction
normal. pressure is higher than
• Superheat
normal. is
• Condenser
0°F. is
• Outdoor
clean. fan operation is
• Sub-cooling
normal. is
25°F.
Which of the following is most likely the
problem?
a. Capillary tube partially
blocked.
b. Non-condensables in the
system.
c. Overcharge of
refrigerant.
, d. Lack of air across the indoor coil. correct
answers C
Which one of the following can be caused by a restricted
air filter?
a. High evaporator
pressure.
b. High evaporator
temperature.
c. High
superheat.
d. Low superheat. correct
answers D
Which of the following would most likely occur if a crankcase
heater fails?
a. The oil may not be driven out of the
refrigerant.
b. The compressor oil may
freeze
c. up. become trapped in the
Oil may
system.
d. Excess refrigerant may migrate to the crankcase. correct
answers D
Across an r-22 suction line drier, how much pressure drop indicates changing
the drier?
a. 1
psig.
b. 3
psig.
c. 6
psig.
d. 8 psig. correct
answers B
In a fixed orifice air conditioning system, the presence of non-
condensable
system will in the
cause:
a. Low head and low suction
pressure.
b. Low head and high suction
pressure.
c. High head and high suction
pressure.
d. High head and low suction pressure. correct
answers C
A compressor with tight bearings will cause the amperage
draw to:
a. Fall below
normal.
b. Rise above
normal.
c. Remain
d. Vary in relation to the ambient temperature. correct
normal.
answers B
Which of the following can be caused by insufficient
airflow?
a. Increased compressor
failure.
b. Increased RH level in indoor
air.
c. Increased cooling
capacity.
d. Increased suction pressure. correct
answers A
conditioning
After a vacuum pump has been used, a continuous pressure rise in the
system
likely most
indicates
the:
a. Presence of
moisture.
b. Existence of a
leak.
c. Presence of residual
refrigerant.
d. Presence of non-condensable gasses. correct
answers B
After a vacuum has been pulled to 500 microns, a pressure rise in a system,
followed
a levelingbyoff at 1500 microns, most likely
indicates the:
a. Existence of a
leak.
b. Presence of
moisture.
c. Existence of a good
vacuum.
d. Presence of non-condensable gases. correct
answers B
On initial start-up of an air conditioning system, the temperature drop
measured
the across
evaporator coil exceeds manufacturer's specifications. this condition
most likely
indicates
a/an:
a. Excessive
airflow.
b. Insufficient
c. Lack of refrigerant
airflow.
charge.
d. Refrigerant overcharge. correct
answers B
The technician is on a spring maintenance check of an air
conditioning system.
They find the
• Head pressure is higher than
following:
• Suction
normal. pressure is higher than
• Superheat
normal. is
• Condenser
0°F. is
• Outdoor
clean. fan operation is
• Sub-cooling
normal. is
25°F.
Which of the following is most likely the
problem?
a. Capillary tube partially
blocked.
b. Non-condensables in the
system.
c. Overcharge of
refrigerant.
, d. Lack of air across the indoor coil. correct
answers C
Which one of the following can be caused by a restricted
air filter?
a. High evaporator
pressure.
b. High evaporator
temperature.
c. High
superheat.
d. Low superheat. correct
answers D
Which of the following would most likely occur if a crankcase
heater fails?
a. The oil may not be driven out of the
refrigerant.
b. The compressor oil may
freeze
c. up. become trapped in the
Oil may
system.
d. Excess refrigerant may migrate to the crankcase. correct
answers D
Across an r-22 suction line drier, how much pressure drop indicates changing
the drier?
a. 1
psig.
b. 3
psig.
c. 6
psig.
d. 8 psig. correct
answers B
In a fixed orifice air conditioning system, the presence of non-
condensable
system will in the
cause:
a. Low head and low suction
pressure.
b. Low head and high suction
pressure.
c. High head and high suction
pressure.
d. High head and low suction pressure. correct
answers C
A compressor with tight bearings will cause the amperage
draw to:
a. Fall below
normal.
b. Rise above
normal.
c. Remain
d. Vary in relation to the ambient temperature. correct
normal.
answers B
Which of the following can be caused by insufficient
airflow?
a. Increased compressor
failure.
b. Increased RH level in indoor
air.
c. Increased cooling
capacity.
d. Increased suction pressure. correct
answers A
