NATE Exam Air Conditioning and Heat Pumps
Pt 2 Exam Questions with 100% Correct
Answers
What must be verified before you use performance charts or tables to validate system operation?
a. Refrigerant charge
b. Correct air flow
c. Check the voltage
d. All the above
b (Correct air flow)
What may be needed to protect the compressor from refrigerant slugging?
a. driers
b. heaters
c. more refrigerant
d. accumulator
d (accumulator)
What is designed to boil off liquid refrigerant before it reaches the compressor and allow oil to return
in small, manageable amounts?
a. TEV
b. crankcase heaters
c. accumulator
d. evaporator
c (accumulator)
What is used to maintain the correct superheat when larger coils are used?
a. more refrigerant
b. TEV
c. Check valves
d. all the above
b (TEV)
A switchover valve is also known as a __________.
a. Reversing valve
b. TEV
c. heat pump
d. check valve
a (Reversing valve)
If the vacuum reading rises to a value less than 2,500 microns and levels off at that point, the circuit
has___________
a. reached a complete vacuum
b. a leak
c. no leaks but water vapors remains in the circuit.
,d. refrigerant still in the system
c (no leaks but water vapors remains in the circuit.)
If the vacuum reading rises above 2,500 microns and continue to rise, _________ exist in the circuit.
a. reached a complete vacuum
b. a leak
c. no leaks but water vapors remains in the circuit
d. refrigerant still in the system
b (a leak)
Adding refrigerant charge _________superheat.
a. decreases
b. increases
c. eliminate
d. overloads
a (decreases)
Removing refrigerant ____________ superheat.
a. decreases
b. increases
c. eliminate
d. overloads
b (increases)
When measured 18 in. from the compressor, superheat should range from ________ to ______for a
system that uses a TEV for cooling cycle.
a. 15-20°F
b. 0-15°F
c. 20-30°F
d. 25-35°F
c (20-30°F)
Correct refrigerant charge for a system that uses a fixed-orifice metering device is confirmed by using
the _____________measurement.
a. superheat
b. subcooling
c. Flashing
d. all the above
a (superheat)
Correct refrigerant charge for a system which the evaporator is fed by a TEV metering device is
confirmed by using the _____________ measurement.
a. superheat
b. subcooling
c. Flashing
, d. all the above
b (subcooling)
When the liquid line is lower than the ambient air temperature the problem is?
a. lack of air flow
b. vapor-line restriction
c. the compressor
d. liquid-line restriction
d (liquid-line restriction)
If the liquid-line temperature at the indoor and outdoor sections are nearly equal, what is the
problem?
a. the compressor
b. vapor-line restriction
c. a restriction exist in the metering device or the distributor
d. liquid-line restriction
c (a restriction exist in the metering device or the distributor)
A change in dry-bulb temperature readings between the entering points of the return grille and the
evaporator coil or between the leaving point of the evaporator coil and the supply outlet indicates
what?
a. incorrect refrigerant charge
b. lack of air flow
c. bad compressor
d. return or supply duct leakage, insufficient insulation, or both
d (return or supply duct leakage, insufficient insulation, or both)
Air follows the path of ________just as electric does.
a. current
b. least resistance
c. most resistance
d. all the above
b (least resistance)
What Manual ___ provides excellent guidelines for use in residential designing ductwork.
a. D
b. Q
c. N
d. J
a (D)
Average air velocity is 675 ft/min in a section of duct that measures 25 in x 10 in. calculate the volume
of air flow.
a.1,688 cfm
b. 2.7 cfm
Pt 2 Exam Questions with 100% Correct
Answers
What must be verified before you use performance charts or tables to validate system operation?
a. Refrigerant charge
b. Correct air flow
c. Check the voltage
d. All the above
b (Correct air flow)
What may be needed to protect the compressor from refrigerant slugging?
a. driers
b. heaters
c. more refrigerant
d. accumulator
d (accumulator)
What is designed to boil off liquid refrigerant before it reaches the compressor and allow oil to return
in small, manageable amounts?
a. TEV
b. crankcase heaters
c. accumulator
d. evaporator
c (accumulator)
What is used to maintain the correct superheat when larger coils are used?
a. more refrigerant
b. TEV
c. Check valves
d. all the above
b (TEV)
A switchover valve is also known as a __________.
a. Reversing valve
b. TEV
c. heat pump
d. check valve
a (Reversing valve)
If the vacuum reading rises to a value less than 2,500 microns and levels off at that point, the circuit
has___________
a. reached a complete vacuum
b. a leak
c. no leaks but water vapors remains in the circuit.
,d. refrigerant still in the system
c (no leaks but water vapors remains in the circuit.)
If the vacuum reading rises above 2,500 microns and continue to rise, _________ exist in the circuit.
a. reached a complete vacuum
b. a leak
c. no leaks but water vapors remains in the circuit
d. refrigerant still in the system
b (a leak)
Adding refrigerant charge _________superheat.
a. decreases
b. increases
c. eliminate
d. overloads
a (decreases)
Removing refrigerant ____________ superheat.
a. decreases
b. increases
c. eliminate
d. overloads
b (increases)
When measured 18 in. from the compressor, superheat should range from ________ to ______for a
system that uses a TEV for cooling cycle.
a. 15-20°F
b. 0-15°F
c. 20-30°F
d. 25-35°F
c (20-30°F)
Correct refrigerant charge for a system that uses a fixed-orifice metering device is confirmed by using
the _____________measurement.
a. superheat
b. subcooling
c. Flashing
d. all the above
a (superheat)
Correct refrigerant charge for a system which the evaporator is fed by a TEV metering device is
confirmed by using the _____________ measurement.
a. superheat
b. subcooling
c. Flashing
, d. all the above
b (subcooling)
When the liquid line is lower than the ambient air temperature the problem is?
a. lack of air flow
b. vapor-line restriction
c. the compressor
d. liquid-line restriction
d (liquid-line restriction)
If the liquid-line temperature at the indoor and outdoor sections are nearly equal, what is the
problem?
a. the compressor
b. vapor-line restriction
c. a restriction exist in the metering device or the distributor
d. liquid-line restriction
c (a restriction exist in the metering device or the distributor)
A change in dry-bulb temperature readings between the entering points of the return grille and the
evaporator coil or between the leaving point of the evaporator coil and the supply outlet indicates
what?
a. incorrect refrigerant charge
b. lack of air flow
c. bad compressor
d. return or supply duct leakage, insufficient insulation, or both
d (return or supply duct leakage, insufficient insulation, or both)
Air follows the path of ________just as electric does.
a. current
b. least resistance
c. most resistance
d. all the above
b (least resistance)
What Manual ___ provides excellent guidelines for use in residential designing ductwork.
a. D
b. Q
c. N
d. J
a (D)
Average air velocity is 675 ft/min in a section of duct that measures 25 in x 10 in. calculate the volume
of air flow.
a.1,688 cfm
b. 2.7 cfm
