Refrigeration RT/RC Prep Quiz

Topics: All categories in the pool

Quiz Result Settings

1: Which of the following are considered inorganic refrigerants?

  • R-717 and R-718
  • 410A and R-407C
  • R-500 and R-502
  • None of the above

2: What is specific heat?

  • measured heat
  • heat required to raise the temperature of 1lb of a substance 1 degree
  • the specific heat required to change the state of one cubic foot of air to steam
  • none of the above

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

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

4: Low ambient controls are used when

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

5: If a refrigerant leaving the condenser is 94F and the condensing temperature is 105F, the subcooling is

  • 29F
  • 9F
  • 21F
  • 11F

6: The measurement of heat in a particular substance is

  • latent heat
  • enthalpy
  • sensible heat
  • specific heat

7: A class B1 refrigerant is considered

  • non-toxic and non-flammable
  • non-toxic but highly flammable
  • toxic and somewhat flammable
  • toxic but non-flammable

8: Ohm's Law indicates Amps X Resistance = ___________.

  • Impedance
  • Current
  • Ohms
  • Volts

9: How are safety controls wired in a circuit?

  • Either series or parallel
  • Series
  • Series/parallel
  • Parallel

10: A single pole-double throw switch used how many wires excluding the ground wire?

  • three
  • two
  • five
  • four

11: What is absolute humidity?

  • the amount of moisture in the air per one pound of 50% RH air
  • the amount of moisture in the air in grains of cubic feet of volume
  • the amount of moisture in the air in grains of square feet of volume
  • none of the above

12: If the dry bulb temperature is 85F and the wet bulb temperature is 70F, the dew point temperature will be approximately (use psychometric chart)

  • 77F
  • 70F
  • 32F
  • 58F

13: If your suction line is warmer than the room temperature, this may indicate

  • a low charge
  • an over charge
  • below normal superheat
  • plugged air filter

14: What is not a requirement of a class T machine room?

  • fire hose connection to the building fire protection system
  • tight fitting doors
  • automatic ventilation
  • self-closing doors

15: A compressor that increases vapor pressure by changing the internal volume of the compression chamber is called?

  • Pressure induced displacement.
  • Positive displacement
  • Non-positive displacement
  • Low Pressure displacement

16: Megaohm meter's main function is

  • to detect weak motor winding insulation of a refrigeration or air conditioning compressor by creating high DC voltages to the compressor
  • to detect very high resistances to ground of refrigeration or air conditioning compressors
  • to test very high value capacitors for large 3-phase refrigeration compressors and blower motors.
  • Both a and b are correct

17: Where a refrigeration or air conditioning system is installed,

  • it shall not be operated below prescribed pressuers
  • A field inspection shall be made before it is put into service
  • The company who installed the system must notify the fire department in the jurisdiction where installed
  • the form or certificate shall be authorized by the Department of Public Safety

18: When an A/C system is excessively low on refrigerant

  • it can become contaminated with water
  • there can be nuisance trip outs
  • the suction line may be too hot to touch
  • All of the above

19: 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.

20: Group A1 refrigerants over ____ pounds in a system must discharge to the atmosphere

  • 330
  • 110
  • 6.6
  • 1,000

21: Class A refrigerants are considered

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

22: A pressure vessel having an inside diameter of 6” or less shall be sufficient to withstand ____times the pressure of the saturation temperature of the refrigerant or ____times the critical pressure of the refrigerant, whichever is less.

  • 2.5, 3.0
  • 3.0, 3.5
  • 6.6, 6.6
  • 2.5, 2.5

23: The outer portion of shell of the compressor used on low-pressure chillers is called the

  • volute
  • suction
  • nozzle
  • baffle

24: A hissing noise at the expansion valve is a good indication that

  • expansion valve is oversized
  • gas is passing thru it
  • nothing is passing thru
  • liquid is passing thru it

25: The main purpose of a refrigerant detector in a machinery room is to

  • inform there is a refrigerant leak int he system
  • detect toxins in the air caused by a refrigerant leak
  • to set off an alarm when there is refrigerant present inside the room
  • all of the above