Refrigeration RT/RC Prep Quiz

Topics: All categories in the pool

Quiz Result Settings

1: Emergency shutdown procedures, including precautions to be observed in case of a breakdown or leak over 55 lbs of refrigerant charge, shall be displayed on a conspicuous card located as near as possible to the

  • evaporator
  • boiler
  • compressor
  • outside the machinery room

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

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

3: Liquid refrigerant flashing, or turning to vapor, in the liquid line may be due to

  • liquid line that is too small
  • shortage of refrigerant
  • liquid line that had too high vertical lift
  • All of the above

4: A self contained system

  • is a unit system Group I refrigerants only
  • is a complete factory made and tested system
  • is a unit system Group II refrigerants only
  • is any system or part of a system used to increase evaporation by expansion or vaporization

5: On a 460V motor, what is he MAXIMUM voltage that can be safely applied to it?

  • 506v
  • 550v
  • 660v
  • None of the above

6: Calculate the voltage in a series circuit when the total amperage is 10 amps and the resistors have values of: R1=12 ohms, R2=8 ohms, R3=4 ohms

  • 24.0 volts
  • 2,400 volts
  • 240 volts
  • 2.40 volts

7: What is the boiling point of refrigerant governed by?

  • Condenser sub-cooling
  • Compressor RPM's
  • P&T relationship
  • Evaporator temperature

8: Institutional occupancy is

  • a premise or that portion of a premise where large numbers of people congregate and from which occupants cannot quickly vacate the space.
  • a premise or that portion of a premise from which, because they are disabled, debilitated, or confined, occupants cannot readily leave without the assistance of others.
  • a premise or that portion of a premise where people transact business, receive personal service, or purchase food and other goods.
  • None of the above

9: A normal operating evaporator temperature of R-22 for air conditioning is typically

  • 45F
  • 58F
  • 32F
  • 55F

10: It takes how many BTU/hr to melt one pound of ice at 32F

  • 970
  • 180
  • 144
  • 212

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

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

12: The 4 basic methods of determining whether the proper amount of refrigerant is being introduced into the system are

  • Buss-eye, weight, pressure, and frost line
  • sight glass, weight, paper method, and frost line.
  • sight glass, weight, pressure, and frost line
  • sight glass, weight, pressure, and dipstick

13: What is the minimum size of the discharge pipe?

  • Same size as the outlet of the relief valve
  • One pipe size larger that the inlet of the relief valve
  • Depends on size of manifold
  • All of the above

14: Each machinery room shall contain

  • a refrigerant detector located in an area where the refrigerant from a leak will concentrate
  • high and low pressure controls
  • smoke and fire alarms as well as three means of egress and that egress must meet 528 CMR ventilation requirements
  • a toxicity detector where the presence of ammonia or lithium bromide from a leak will concentrate

15: In an air conditioning system, the unit of total heat energy content in an air/vapor mixture is

  • Latent heat
  • Sensible heat
  • Specific heat
  • Enthalpy

16: On a single phase motor, when does the start winding cut out?

  • At 25% of its full rated speed
  • At 50% of its full rated speed
  • Start windings do no cut-out of the run cycle
  • At 75% of its full rated speed

17: What is the voltage of each leg to ground of a three-phase motor with a 460v supply voltage?

  • 240v
  • 277v
  • 208v
  • 120v

18: The oil separator is always inserted in the system

  • in the discharge line
  • to prevent oil logging
  • where it can be easily serviced
  • in a cool spot

19: One watt of electrical energy in a resistive heater will provide _____ BTU/hr

  • 34.15
  • 6.830
  • 3.415
  • 16.64

20: What is the temperature that a liquid and a vapor can exist in equilibrium called?

  • Dry bulb temperature
  • Saturated temperature
  • Wet bulb temperature
  • Critical temperature

21: "R" represents ___ in the Ohm's law formula

  • resistance
  • capacitance
  • voltage
  • amperage

22: Before you change the type of refrigerant in a refrigeration system, what three things must be done?

  • Place sign, check for leaks, and insulate suction line
  • Make sure its compatible, notify owner, and notify AHJ.
  • you can never change refrigerants
  • Nothing must be done

23: The discharge relief valve is located (9.4.6)

  • between the compressor and reciever
  • between the compressor and the stop valve
  • on top of the condensor
  • between the compressor and oil separator

24: Evaporators within 18" of a heating coil must be equipped with a

  • high limit control
  • pressure relief device
  • zone valve
  • low limit control

25: The color code of a tank of ammonia is

  • silver
  • light green
  • lavender
  • white