Topics: All categories in the pool
1: What device should be used on low-temperature freezers?
- hot-gas by-pass
- high capacity TXV
- oil separator
- discharge muffler
2: What measures gas pressure?
- Manometer
- Hygrometer
- Barometer
- Hydrometer
3: How does a centrifugal compressor create the pressure differential needed to move refrigerant through the system?
- Suction and discharge valves
- Fan-like action
- Nesting scrolls
- Rotating vanes
4: What is the refrigerant chlorodifluoromethane?
- R-123
- R-12
- R-134a
- R-22
5: Fusible plugs must have what marked on them?
- Melting temperature in F
- Melting temperature in C
- Opening pressure
- All of the above
6: The purpose of a receiver is
- a vessel to store refrigerant outside the system
- to increase the capacity that the system can hold
- to use a a later date
- all of the above
7: Low-side system leaks in a low-pressure chiller will often result in
- water being pulled into the system
- air being pulled into the system
- nitrogen leaking out of the system.
- system refrigerant leaking from the system
8: A rule of thumb in air conditioning is ____ CFM per ton?
- 600
- 500
- 400
- 100
9: A motor starter contains a thermal overload and a
- transformer
- 3-way relay
- contactor
- solenoid
10: Total heat of a substance is considered
- specific heat
- empathetical
- sensible heat
- enthalpy
11: How can you test mechanical strength of an electrical connection?
- measure ohms with an electrical meter
- measure voltage across the connection
- attempt to pull the wire from the connector by hand
- none of the above.
12: A Lithium-bromide system is an absorption system that
- uses water as a absorbent and lithium bromide as a refrigerant
- uses water as a refrigerant and lithium bromide as an absorbent
- uses salts as an absorbent and lithium bromide as a refrigerant
- uses ammonia as a refrigerant and lithium bromide as an absorbent
13: A cross charged power element on an expansion valve would normally be used in what temperature range?
- -40F to 0F
- 0F-38F
- -100F to -40F
- 30F to 50F
14: What will occur if the strong solution in an absorption chiller becomes too strong?
- The machine will cool excessively as the solution crystallizes.
- The machine will stop cooling and solution will crystallize
- The machine will cool excessively as the solution evaporates
- The machine will stop cooling and the solution will evaporate.
15: The leaving chilled water set point for comfort cooling is typically?
- 66
- 45
- 60
- 38
16: If the dry bulb temperature is 85F and the wet bulb temperature is 70F, the dew point temperature will be approximately (use psychometric chart)
- 58F
- 70F
- 32F
- 77F
17: When energized, a normally open relay will be
- closed
- open
- depends on the type and class of the relay
- noisy
18: In an electrical circuit, what is potential measured in?
- Herys
- Ohms
- Volts
- Amps
19: Which creates more of a heat load?
- 70% RH
- 50% RH
- 90% RH
- 30% RH
20: Which of the following most closely represents the concentration of Li-Br in a absorption system?
- 60% Li-Br, 40% distilled water
- 40% Li-Br, 60% distilled water
- 40% Li-Br, 60% tap water
- 50% Li-Br, 50% tap water
21: What is the boiling point of refrigerant governed by?
- P&T relationship
- Condenser sub-cooling
- Evaporator temperature
- Compressor RPM's
22: Ammonia (NH3) is a group III refrigerant
- True
- False
23: What is not a requirement of a Class T machine room?
- Fire hose connected to the building fire protection system.
- Tight fitting doors
- Automatic ventilation
- Self-closing doors
24: It shall be the duty of the person in charge of the premises on which a refrigeration system containing more than ___ lbs of refrigerant is installed to provide a schematic drawing or panel giving directions for the operation of the system.
- 75
- 15
- 50
- 55
25: Liquid level gauges shall have _____________ with one exception being that of the liquid level gauge bull’s eye type.
- color-coded glass to determine type of refrigerant
- moisture indicators
- automatic closing shut-off valves
- All of the above