Refrigeration RT/RC Prep Quiz

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Quiz Result Settings

1: In a low temperature refrigeration system, the benefit of the system using P.A.G. oil is

  • it is hydroscopic
  • it traps moisture
  • viscosity
  • all of the above

2: The actual expansion curve of compression follows most nearly which one of the following curves?

  • Volume Temperature
  • Pressure Temperature
  • Isothermal
  • Adiabatic

3: Ammonia vaporization takes place at what temperature?

  • -110F
  • -32F
  • -28F
  • -460F

4: The normal operating evaporator temperature of R-410A for air conditioning is typically

  • 155F
  • 158F
  • 45F
  • 32F

5: A “U” or “UM” marking a on a nameplate of a pressure vessels signifies compliance with Section VIII of

  • the ASME Boiler and Pressure Vessel Code
  • Section 11.3.1.5 ASHRAE 15 Standard
  • the ANSI Standard 10.7.2
  • both the ANSI Standard 10.7.2 and ASHRAE 15 Standard 11.3.1.5

6: Suction line oil traps should be installed when the condenser is

  • more than 100' away from the evaporator
  • in the basement and the evaporator is on the third floor
  • located outside the operates in temperatures below 35F
  • on the third floor roof and the evaporator is in the basement

7: Laten heat is associated with a change in state of a refrigerant but not temperature

  • True
  • False

8: The high side float assembly meters refrigerant into the evaporator through the

  • lower chamber of the high side
  • upper chamber of the high side
  • upper chamber of the low side
  • lower chamber of the low side

9: 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

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

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

11: Low ambient controls are used when

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

12: Before replacing a seized compressor, the _______ should be determinded.

  • designed head pressure
  • current draw
  • type of refrigerant
  • cause of seizure

13: What is the typical air conditioning operating pressures for R-22?

  • 60 psi suction 210 psi discharge
  • 25 psi suction 125 psi discharge
  • 105 psi suction 340 psi discharge
  • None of the above

14: To determine the pump size needed for an open cooling tower system, the following must be known,

  • GPM, pipe size, and equivalent head.
  • GPM and unbalanced head and friction head
  • GPM and friction head
  • GPM and balanced head and friction head

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

  • suction
  • nozzle
  • volute
  • baffle

16: Which refrigerant was still able to be vented to the atmosphere after July 1, 1992?

  • R-22
  • R-11
  • R-12
  • R-113

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

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

18: 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

19: Systems containing more than 110 pounds must have stop valves located at the

  • compressor suction inlet
  • compressor discharge outlet
  • receiver inlet and outlet
  • All of the above

20: Which of the following most closely represents the concentration of Li-Br in a absorption system?

  • 60% Li-Br, 40% distilled water
  • 50% Li-Br, 50% tap water
  • 40% Li-Br, 60% tap water
  • 40% Li-Br, 60% distilled water

21: 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

22: Group A2 refrigerants have a ______ toxicity rating than Group B1 refrigerants.

  • lower
  • there is no Group B1 refrigerants
  • higher
  • the same

23: Atmospheric pressure is equal to

  • 29.92" Hg
  • 14.7 psia
  • 14.7 psig
  • both a & b

24: What happens after your initial inspection of a pressure vessel?

  • Notify the Fire Marshal that the system has been inspected and approved
  • Inspector leaves a metal tag with a certification listed on it
  • There is a temporary shut-down until a final inspection can be performed.
  • Notify the AHJ to let them know that the system been inspected

25: All low-pressure chillers use which type of compressor?

  • Rotary
  • Scroll
  • Centrifugal
  • Reciprocating