Topics: All categories in the pool
1: On a centrifugal compressor, stationary diffuser vanes are needed to
- prevent high pressure on the packing
- convert velocity energy to pressure
- stop gas flow
- increase the clearance space
2: The Board of Boilers adopts by reference
- Montreal Protocol Safety Code
- the 1997 ANSI/ASHRAE Safety Code
- MSCA Code
- the MACS Pressure Vessel Code of Massachusetts
3: R-718 is rated unlimited for refrigeration quantity contained in a system. Why?
- Because it's water
- Because it's a non-flammable refrigerant
- Because it's cheap
- R-718 is not rated unlimited because it's a dangerous refrigerant
4: Which is considered the more efficient condenser?
- fan cooled
- air cooled
- spray cooled
- water cooled
5: The gauge thickness required on a CO2 tank construction is
- 1/16"
- 1/8"
- 3/32"
- 5/16"
6: When systems are protected by a high pressure relief device, the compressor's pressure limiting device shall be set at or below ____ % of the operating pressure of the high side relief device.
- 90
- 100
- 110
- 80
7: The actual expansion curve of compression follows most nearly which one of the following curves?
- Volume Temperature
- Pressure Temperature
- Adiabatic
- Isothermal
8: A compressor in which the increase in vapor pressure is attained without changing the internal volume of the compression chamber is called
- non-volumetric displacement compressor
- non-positive displacement compressor
- negative displacement compressor
- neutral chamber-type compressor
9: A split-phase motor has a ______ winding and a ____ winding
- duel-run, duel-start
- start, common
- run, start
- run, common
10: Ammonia shall be discharged into ____________ or a tank containing one gallon of water for every pound of ammonia.
- the atmosphere
- a de-pressurized recovery tank with a silver top and yellow bottom
- a tank containing two pounds of a water/lithium bromide mix for every pound of ammonia
- All of the above
11: High side floats are used on centrifugal chiller systems are are considered critically charged systems.
- depends on the type of refrigerant being used
- True
- are obsolete.
- False
12: What happens to copper joints when overheated?
- nothing
- joint becomes oxidized and ditorted
- copper becomes harder
- none of the above
13: What type of relief valve is used on low pressure centrifugal compressor systems?
- Spring-loaded relief valve
- Rupture disc
- Purge relief
- None of the above
14: Relief valves are rated in
- gallons of water per minute
- gallons of water per hour
- pounds of air per minute
- pounds of air per hour
15: 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 dipstick
- sight glass, weight, pressure, and frost line
16: A secondary coolant is defined as
- any liquid used for the transmission of heat without a change of state in A/C refrigeration systems having flash point above 150F
- any refrigerant direcly in contact with the cooling space for process cooling
- a combination of interconnected parts from a closed circuit in where fluid is circulated for the purpose of cooling for a refrigeration system.
- a low temperature refrigerant used for cascading systems
17: One watt of electrical energy in a resistive heater will provide _____ BTU/hr
- 3.415
- 16.64
- 34.15
- 6.830
18: Pressure vessels shall be provided with ___________in accordance with Section VIII of the ASME Boiler & Pressure Vessel Code
- over pressure protection
- Pressure vessels need no type of protection as long as it is hydrostatically tested every three months
- over pressure protection and a rupture disc
- over pressure protection as well as a temperature protection device
19: Before replacing a seized compressor, the _______ should be determinded.
- type of refrigerant
- current draw
- cause of seizure
- designed head pressure
20: What effect does the temperature of air have on humidity?
- warmer air holds more moisture then cooler air
- cooler air holds more moisture then warmer air
- air has no effect of humidity
- none of the above
21: R-12 is
- dichloromethane
- trichlorofluoromethane
- dichlorodifluoromethane
- dichlorofluoromethane
22: Which occupancy can ammonia be used in?
- commercial
- depends on the quantity of freon
- redifential
- industrial
23: What is considered a cooling agent?
- any liquid used for the transmission of heat without vaporization
- any liquid used for the transmission of heat when vaporization occurs
- any liquid used for the transmission of heat without condensation
- any liquid used for the transmission of heat when condensation occur
24: Capacity control on an absorption system is typically accomplished by varying the
- rate at which heat is supplied to the generator
- speed of the chilled water circulatory pump
- speed of the condenser water circulator pump
- pressure setting on the system's rupture disc
25: When should a relief valve start to function?
- Before the purge station discharges
- At it's set pressure
- 10 psi before it's set pressure
- Two times it's working pressure