Refrigeration RT/RC Prep Quiz

Topics: All categories in the pool

Quiz Result Settings

1: Pi equals approximately

  • 3.41
  • 12,000
  • 746
  • 3.14

2: Suction valve unloaders afford an effective means of

  • evaporator control
  • capacity control
  • superheat control
  • refrigerant control

3: A line voltage thermostat controls a 1,200 watt strip header at 120 volts. What must be minimum ampere rated of the stat be?

  • 10 amps
  • 15 amps
  • 5 amps
  • 20 amps

4: Ammonia can come in contact with _______ ?

  • Copper tubing
  • Copper
  • Aluminum
  • Brass

5: Pressure is equivalent of

  • Area X Force
  • Force X Area
  • Force
  • Force / Area

6: copper and its alloys shall not be used in contact with _____ except as a component of bronze alloys for bearing or other non-refrigerant containing uses.

  • CFC-11
  • ammonia
  • Lithium bromide
  • HCFC-123

7: If air is present in an absorption chilled water appliance, which of the following will most likely occur?

  • Rust can form
  • System operating pressure will drop
  • The Li-Br solution will become more diluted
  • The Li-Br solution will become more concentrated

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

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

9: A single pole-double throw switch uses how many wires?(excluding the ground)

  • 5
  • 2
  • 3
  • 4

10: What type of material can't be used on the outlet of a relief valve?

  • Copper
  • Magnesium alloy
  • PVC
  • Stainless steel

11: By using nitrogen within a pipe during brazing operation,

  • Copper oxide formation is prevented
  • The explosion hazard is confined
  • Exterior scale formation is minimized
  • Discoloration is prevented

12: Ammonia vaporization takes place at what temperature?

  • -110F
  • -460F
  • -32F
  • -28F

13: The low pressure oil safety switch

  • must be reset manually
  • resets itself after the time delay has terminated
  • never trips
  • resets itself automatically

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

  • 100% of its RLA speed
  • 75% of its RLA speed
  • 50% of its RLA speed
  • 25% of its RLA speed

15: A R-410A system running with a condensing temperature of 110F and 50F evaporator temperature will read pressures of ___ on the high side and ___ on the low side

  • 226 psig, 68 psig
  • 365 psig, 120 psig
  • 257 psig, 77 psig
  • 455 psig, 185 psig.

16: Brazed joints melt at temperatures above

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

17: Which of the following types of oils are hygroscopic?

  • polyolester (POE)
  • polyalkylene glycol (PAG)
  • naphthene mineral
  • both a and b

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

  • 32F
  • 70F
  • 58F
  • 77F

19: Joints in piping for refrigeration containing parts must withstand temperatures of ___?

  • 800F
  • 700F
  • 600F
  • 1000F

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

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

21: Heat cannot of itself, pass from a

  • cold to a warmer body
  • warm to a colder body
  • state of hot energy to a state of cold energy
  • None of the above

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

  • 208v
  • 277v
  • 240v
  • 120v

23: Where must a refrigeration contractor's license number be displayed?

  • Trucks, invoices, and advertising
  • Uniforms, checks, and invoices.
  • Truck, office, every job, and on all equipment
  • Trucks, license plates, and uniforms

24: Pressure vessels with an internal volume of 3 cubic feet or less

  • shall use pressure relief devices
  • do not need pressure relief protection
  • shall use fusible plugs
  • shall use pressure relief devices or fusible plugs

25: "E" represents _____ in the Watt's law formula.

  • voltage
  • reactance
  • watts
  • amperage