8. NATE Industry Competency Exam: Commercial Refrigeration TESTS WITH ANSWERS A+
GRADE.
The compressor capacity should be selected based on a saturated suction temperature of:
a. 20°F.
b. 21°F.
c. 23°F.
d. 25°F. - B
What is true of systems with multiple evaporators at different temperatures?
a. It is required to install evaporator pressure regulator(s).
b. The compressor discharge pressure will be a function of the coldest space.
c. It is required to install a head pressure control valve.
d. It is required to install a crankcase pressure regulator. - A
If charging a system by subcooling, what metering devices is installed?
a. Capillary tube.
b. Restrictor.
c. Thermostatic expansion valve.
d. Fixed orifice. - C
The most critical refrigerant line with respect to sizing for compressor performance is the:
a. Liquid line.
b. Discharge line.
c. Suction line.
d. Bypass line. - C
,In a liquid line, excess pressure drop can cause:
a. Sweating suction lines.
b. Flash gas.
c. Compressor overload.
d. Liquid subcooling. - B
What are the two factors making up the safety classification for refrigerants?
a. Toxicity and time weighted average.
b. Toxicity and flammability.
c. Emergency exposure limit and time weighted average.
d. Flammability and TEWI. - B
What would be most affected by the use of an oversized suction line?
a. Discharge temperature.
b. Oil return.
c. Return gas temperature.
d. Refrigerant migration. - B
On an electrical diagram, the below symbol represents a control that:
a. Closes on pressure rise.
b. Opens on pressure rise.
c. Closes on temperature fall.
d. Opens on temperature rise. - B
, During the pulldown periods of single compressor condensing units, compressor overloading can best be
prevented by using a(n):
a. Thermostatic expansion valve.
b. Evaporator pressure regulating valve.
c. Crankcase pressure regulating valve.
d. Head pressure valve. - C
The purpose of a crankcase heater is to:
a. Reduce refrigerant migration into the oil during the off cycle.
b. Minimize refrigerant flooding into the compressor.
c. Remove any oil that may have migrated into the refrigerant.
d. Warm the oil to allow compressors to start easier. - A
An electrical motor is designed to operate 120/240 volts. In using 120 volts, the current draw is 10
amperes. What would the current draw in using 240 volts?
a. 10 A.
b. 5 A.
c. 2.5 A.
d. 20 A. - B
If the cut-out setting is raised 10°F and the differential doses not change, what is the effect on the cut-in
setting?
a. No effect on the cut-in.
b. The cut-in is lowered 10°F.
c. The cut-in is raised 10°F.
d. The cut-in is raised 20°F. - C
GRADE.
The compressor capacity should be selected based on a saturated suction temperature of:
a. 20°F.
b. 21°F.
c. 23°F.
d. 25°F. - B
What is true of systems with multiple evaporators at different temperatures?
a. It is required to install evaporator pressure regulator(s).
b. The compressor discharge pressure will be a function of the coldest space.
c. It is required to install a head pressure control valve.
d. It is required to install a crankcase pressure regulator. - A
If charging a system by subcooling, what metering devices is installed?
a. Capillary tube.
b. Restrictor.
c. Thermostatic expansion valve.
d. Fixed orifice. - C
The most critical refrigerant line with respect to sizing for compressor performance is the:
a. Liquid line.
b. Discharge line.
c. Suction line.
d. Bypass line. - C
,In a liquid line, excess pressure drop can cause:
a. Sweating suction lines.
b. Flash gas.
c. Compressor overload.
d. Liquid subcooling. - B
What are the two factors making up the safety classification for refrigerants?
a. Toxicity and time weighted average.
b. Toxicity and flammability.
c. Emergency exposure limit and time weighted average.
d. Flammability and TEWI. - B
What would be most affected by the use of an oversized suction line?
a. Discharge temperature.
b. Oil return.
c. Return gas temperature.
d. Refrigerant migration. - B
On an electrical diagram, the below symbol represents a control that:
a. Closes on pressure rise.
b. Opens on pressure rise.
c. Closes on temperature fall.
d. Opens on temperature rise. - B
, During the pulldown periods of single compressor condensing units, compressor overloading can best be
prevented by using a(n):
a. Thermostatic expansion valve.
b. Evaporator pressure regulating valve.
c. Crankcase pressure regulating valve.
d. Head pressure valve. - C
The purpose of a crankcase heater is to:
a. Reduce refrigerant migration into the oil during the off cycle.
b. Minimize refrigerant flooding into the compressor.
c. Remove any oil that may have migrated into the refrigerant.
d. Warm the oil to allow compressors to start easier. - A
An electrical motor is designed to operate 120/240 volts. In using 120 volts, the current draw is 10
amperes. What would the current draw in using 240 volts?
a. 10 A.
b. 5 A.
c. 2.5 A.
d. 20 A. - B
If the cut-out setting is raised 10°F and the differential doses not change, what is the effect on the cut-in
setting?
a. No effect on the cut-in.
b. The cut-in is lowered 10°F.
c. The cut-in is raised 10°F.
d. The cut-in is raised 20°F. - C
