SCRIPT PRACTICE TEST WITH
PRACTICE QUESTION
SOLUTIONS
◉ What would indicate a restriction (such as dirt or scale) in the
liquid line? Answer: Frost immediately after the restriction
◉ What does solubility mean? Answer: The ability of a
refrigerant to mix with other substances
◉ Charging Vapor —In a compression system, where do you
charge the vapor? Answer: Suction side of the compressor at the
Suction Service Valve
◉ When comparing a brine with s PH of 8 to one with a PH of
10, its alkalinity is: Answer: 100 times greater (ex. PH 8 to PH 9
is 10 times greater)
◉ In an efficiently operating induced draft cooling tower, the
leaving water is between: Answer: Dry bulb and wet bulb
temperature
◉ To produce the desired evaporator temperature, the power
input is reduced by keeping head pressure... Answer: Head
pressure as low as possible & suction pressure as high as needed
◉ The accumulator is usually between the... Answer:
Compressor and evaporator
◉ An oiling system in a large centrifugal system should consist
of at least... Answer: Reservoir, pump and distribution lines
,◉ In an evaporator that chills brine, the greatest cooling effect
on the brine results from the... Answer: Boiling of low pressure
liquid
◉ The flow of weak liquor to the absorber is controlled by
A) gas pressure
B) throttling device
C) float valve
D) pressure of the strong liquor pump Answer: B) throttling
device
◉ The best way of detecting ammonia brine is by using
A) CO2 gas
B) potassium of lime
C) Nessler reagent
D) carbonate of soda Answer: C) Nessler reagent
◉ The best time to purge an ammonia plant with 250 lbs. of
ammonia is
A) during shut-down, because you will lose ammonia
B) while charging the plant
C) during operation
D) none of the above Answer: C) during operation
◉ What will make the strong liquor in the absorber decrease?
A) expansion valve open too much
B) A decrease in evaporator load
C) An increase in evaporator load
D) Too much steam on the generator Answer: B) A decrease in
evaporator load
◉ Which of the following statements is incorrect?
A) A service valve is a key-operated shut-off valve used during
shipment, installation and repairs
B) Brine is a liquid cooled by refrigeration and used for the
transmission of heat
,C) A fusible plug has a set-temperature fusible member to
relieve pressure
D) A rupture member automatically ruptures at a predetermined
temperature Answer: D) A rupture member automatically
ruptures at a predetermined temperature
◉ Oil in a refrigerant should
A) have a high pour point
B) have a low flash point
C) have a high viscosity
D) not contain moisture Answer: D) not contain moisture
◉ In an NH3 dry expansion evaporator with TXV and bulb
clamped properly on the outlet of the evaporator, the superheat
is
A) 7 to 10° F
B) 5 to 9° F
C) 20 to 30° F
D) 1 to 2° F Answer: A) 7 to 10° F
◉ The setting of a fusible plug is
A) 280° F
B) 300° F
C) 380° F
D) 300 psig. Answer: A) 280° F
◉ If the insulation was removed from the bulb of the expansion
valve, what would happen? Answer: Flooded evaporator —the
TXV bulb opens in a range from 45 to 85° F. If the insulation
was removed, the bulb would sense the temperature in the
machine room and keep the TXV open, thus flooding the
evaporator.
◉ On the most common three-phase, four-wire service, the
voltage between any phase and neutral should be
A) 105 volts
B) 120 volts
, C) 208 volts
D) 220 volts Answer: B) 120 volts
◉ A refrigerant overcharge would
A) increase head pressure
B) decrease head pressure
C) decrease solution-side pressure
D) decrease discharge-side pressure Answer: A) increase head
pressure
◉ A dryer is generally installed with other equipment in a
commercial Freon compressor system. The recommended
location of this dryer is on the
A) high-pressure line between condenser and reciever
B) suction line between evaporator and compressor
C) discharge line between compressor and condenser
D) liquid line between receiver and expansion valve Answer: D)
liquid line between receiver and expansion valve
◉ R-22 —What does it smell like? Answer: Odorless
◉ Desirable characteristics of a refrigerant:
A) High __________
B) Low __________ Answer: A) High critical point
B) Low freezing point
◉ Centrifugal Feed Water Pump
A) Start-up procedure
B) Shut-down procedure Answer: A) Start-up procedure
1) Lock-out, tag-out
2) Close discharge valve
3) Open suction valve
4) Turn on
5) Open discharge valve
B) Shut-down procedure
1) Lock-out, tag-out
2) close suction valve