Topics: All categories in the pool
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