Refrigeration RT/RC Prep Quiz

Topics: All categories in the pool

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