Refrigeration RT/RC Prep Quiz

Topics: All categories in the pool

Quiz Result Settings

1: The heat picked up in the evaporator must equal to

  • the heat giving by the condenser
  • the heat gained by the condenser
  • the heat lost by the medium being cooled
  • the heat of compression

2: A VRF system is a direct system

  • true
  • false

3: There can be no airflow from an occupied space through a machine room unless what?

  • System is high velocity
  • System is ducted and sealed
  • Duct is not located in the ceiling
  • None of the above.

4: The measurement of heat in a particular substance is

  • latent heat
  • specific heat
  • enthalpy
  • sensible heat

5: A secondary coolant is defined as

  • a low temperature refrigerant used for cascading systems
  • any liquid used for the transmission of heat without a change of state in A/C refrigeration systems having flash point above 150F
  • any refrigerant direcly in contact with the cooling space for process cooling
  • a combination of interconnected parts from a closed circuit in where fluid is circulated for the purpose of cooling for a refrigeration system.

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

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

7: Which refrigerant is lighter than air?

  • R-123
  • R-717
  • R-11
  • R-134a

8: What does safe access mean?

  • Locked doors
  • A clear unobstructed path to the equipment and controls
  • Well-lit exit signs
  • OSHA approved

9: A compressor in which the increase in vapor pressure is attained without changing the internal volume of the compression chamber is called

  • non-volumetric displacement compressor
  • non-positive displacement compressor
  • negative displacement compressor
  • neutral chamber-type compressor

10: The critical temperature of a refrigerant gas occurs when

  • any increase in pressure will not liquefy the gas
  • any decrease in pressure will cause condensation
  • the gas returns to a liquid
  • the gas is no longer saturated

11: When using nitrogen for brazing, the pressure should be:

  • Very low
  • Slightly below atmospheric
  • 50-100 psig
  • 125 psig

12: Class A refrigerants are considered

  • non-toxic
  • toxic
  • non-flammable
  • flammable

13: A Category D fluid

  • is when the fluid handled is non flammable, nontoxic, and not damaging to human as defined in ANSI/ASME Process Piping.
  • is when the design pressure does not exceed 150 psi
  • a fluid for service piping in which the potential for personnel exposure is judged to cause harm and irreversible damage to those persons exposed to it
  • Both a and b are correct

14: Low ambient controls are used when

  • when systems run all year round
  • economizers are used
  • always
  • on air conditioning systems only

15: A pressure-limiting device isn't required on a factory-sealed system containing less than ____ lbs.

  • 25
  • 22
  • 66
  • 50

16: Low-side system leaks in a low-pressure chiller will often result in

  • water being pulled into the system
  • system refrigerant leaking from the system
  • nitrogen leaking out of the system.
  • air being pulled into the system

17: An example of an "Expendable Refrigerant" is

  • liquid nitrogen
  • lithium bromide
  • liquid oxygen
  • ammonia

18: Sublimation occurs when

  • ice melts and turns to water
  • liquid is formed from a gas
  • gas is formed directly from a solid
  • gas is formed from a liquid

19: Can ammonia be used on domestic system?

  • yes
  • no, unless there is proper ventilation system installed
  • no
  • yes, for systems under 10 tons

20: If the suction pressure is low and the evaporator temperature high, the cause will be a?

  • too small evaporator
  • overcharged
  • compressor suction valve stuck open
  • starved evaporator

21: When this is installed on the high side of a system, it must be capable of reading 1.2 times the design pressure (ASHRAE 15 9.11.3)

  • Pressure gauge
  • Temperature gauge
  • Sight glass gauge
  • All of the above

22: A 120 volt motor rated at 1,800 watts. You find the motor is drawings 25 amps. The motor is

  • drawing RLA and is running as it should
  • drawing LRA and is seized and should be replaced.
  • running hot
  • none of the above

23: Fractionation occurs when

  • when a fraction of refrigerant is added as the full charge
  • the pressures increase as the heat load increases
  • the pressures decreases as the heat load decreases
  • some of the blended refrigerant evaporates or condenses before the rest of the blend

24: When energized, a normally open relay will be

  • open
  • depends on the type and class of the relay
  • noisy
  • closed

25: A chilled water pump's suction gauge reads 10 psig. The discharge gauge reads 48 psig. What is the head in feet the pump is working against?

  • 38
  • 96
  • 88
  • 58