Refrigeration RT/RC Prep Quiz

Topics: All categories in the pool

Quiz Result Settings

1: A tachometer is an instrument used to measure

  • static pressure
  • speed
  • RPM
  • air velocity

2: How many flammability classifications are refrigerants in?

  • 7
  • 2
  • 3
  • 5

3: How do you find net oil pressure on a compressor?

  • discharge pressure - suction pressure
  • gross oil pressure - suction pressure
  • gross oil pressure - discharge pressure
  • all of the above

4: Brazed joints melt at temperatures above

  • 1,200F
  • 800F
  • 1,000F
  • 500F

5: Viscosity is

  • measure of weight
  • the coefficient of external friction
  • the ability of oil to flow
  • a measure of heat content

6: Pressure limiting devices are not required for systems containing less then ________ refrigerants.

  • 6.6 lbs
  • 44 lbs
  • 13.9 lbs
  • 22 lbs

7: What kind of system uses two different refrigerants in separate systems dependent on each other?

  • Simple
  • Cascade
  • Low pressure
  • R-414B

8: Pairs of mating stop valves that allow sections of a system to be joined before opening these valves or separated after closing them are

  • companion or block valves
  • king valves
  • gate or globe valves
  • ball valves

9: A chilled water pump suction gauge reads 10 psig. Discharge gauge reads 48 psig. The head in feet of the pump is working against

  • 108
  • 88
  • 116
  • 38

10: On an air cooled condenser, if the ambient air is 35F and dropping, what's its effect to the condensor?

  • it would make the condenser more efficient
  • it would make the condenser less efficient
  • it would cause the condenser to sweat
  • it would have no effect on the condenser

11: How does a centrifugal compressor create the pressure differential needed to move refrigerant through the system?

  • Suction and discharge valves
  • Fan-like action
  • Nesting scrolls
  • Rotating vanes

12: A chiller entering and leaving temperature difference is?

  • 50 degrees F
  • 20 degrees F
  • 10 degrees F
  • 5 degrees F

13: In an A/C unit, dirty filters will cause

  • low suction pressure
  • high discharge pressure
  • low oil pressure
  • high suction pressur

14: Clearance volume

  • affects compressor capacity
  • varies depending on compressor speed
  • is the same on all compressors
  • has no effect on compressor capacity

15: The ASHRAE Standard 34 requires what type of alarm for equipment rooms using HCFC-123?

  • A group sensing
  • refrigerant sensing
  • CO Sensing
  • phosgene gas sening

16: Foaming of oil in a compressor is most likely to occur

  • when there is insufficient air across the condenser(i.e., dirty coil)
  • when the evaporator temperatures are below 32F
  • at start-up
  • when ambient temperature are low

17: Lithium-bromide, Li-Br, is best characterized as a

  • sugar
  • soil
  • sand
  • salt

18: Atmospheric pressure is equal to

  • 29.92" Hg
  • 14.7 psia
  • 14.7 psig
  • both a & b

19: The certificate of inspection

  • shall be authorized by a notarized insurance company
  • shall be posted and protected from dirt, water, and other elements
  • shall be $20 and an additional fee of $1 for each tone above 20 tons
  • shall be posted on the compressor shell or electrical panel at the unit

20: Indirect systems using Group II refrigerants

  • shall be used in refrigeration system in excess of 1,000 lbs
  • shall be used in refrigeration system less than 1,000 lbs
  • shall be used for mechanical equipment only
  • shall have all refrigerant containing parts except piping, installed in a Class T machine room

21: Liquid level gauge glasses shall have automatic closing shut off valves, except Bull's eye or reflex type.

  • True
  • False

22: What is the minimum height refrigeration piping should be placed against walls?

  • Ceiling height
  • 72"
  • 7.25'
  • 6'

23: High side floats are used on centrifugal chiller systems are are considered critically charged systems.

  • are obsolete.
  • depends on the type of refrigerant being used
  • True
  • False

24: The location of the thermal bulb for the TXV on the evaporator effects

  • both the pressure and temperature in the feeler bulb
  • the amount of superheat required to operate the TXV
  • the amount of liquid in the evaporator
  • the amount of gas in the evaporator

25: On a ammonia compressor, the pressure of a forced fed oil pump is changed by varying the

  • cooling temperature set-point
  • opening at the pump outlet
  • opening at the pump inlet
  • adjustment of the spring tension of the TXV