Topics: All categories in the pool
1: Sublimation occurs when
- liquid is formed from a gas
- gas is formed from a liquid
- ice melts and turns to water
- gas is formed directly from a solid
2: What is specific heat?
- measured heat
- heat required to raise the temperature of 1lb of a substance 1 degree
- the specific heat required to change the state of one cubic foot of air to steam
- none of the above
3: The main purpose of a refrigerant detector in a machinery room is to
- inform there is a refrigerant leak int he system
- detect toxins in the air caused by a refrigerant leak
- to set off an alarm when there is refrigerant present inside the room
- all of the above
4: In designing duct work, pressure and ______ need to be considered
- length
- CFM
- duct sealant used
- all of the above
5: Pressure vessels with an internal volume of 3 cubic feet or more
- shall use fusible plugs
- shall use pressure relief devices or fusible plugs
- do not need pressure relief protection
- shall use pressure relief devices
6: A motor is rated for 120 volts and has a RLA (rated-load amps) of 5 amps. What is the wattage of the motor?
- 1000 watts
- 746 watts
- 600 watts
- 5KW
7: An example of direct system is
- rooftop unit
- chiller
- absorber
- none of the above
8: The pressure relief device of a positive displacement compressor shall discharge in the ______________or in accordance with 9.7.8
- high side of the system
- the liquid side of the system
- low side of the system
- the vapor side of the system
9: If the spring is adjusted to increase the superheat, this new setting will
- allow more liquid into the evaporator
- lengthen the frost line
- shorten the frost line
- have no effect on the frost line
10: Control systems can be classified by
- safety
- tonnage of system
- economy of operation
- source of power
11: If a halide torch is used for leak detection, what color is the flame if it detects a leak?
- blue
- orange
- green
- red
12: What is a high-side float?
- Located in the liquid line entering the evaporator, is a float-type metering device that rises to reduce refrigerant flow when the liquid refrigerant level rises in the high side of the chiller
- An electronic-type metering device that contains a float assembly within the device which can accurately meter refrigerant into the evaporator as the load varies
- Located in the liquid line entering the evaporator, so when the refrigerant level is higher in the liquid line than the evaporator, the float rises to allow more refrigerant flow into the evaporator
- Located in the evaporator, is a float-type metering device that rises to reduce refrigerant flow when the liquid refrigerant level rises in the low side of the chiller
13: What type of oil is used in R-410A systems?
- mineral oil
- polyolester (POE)
- naphthene
- polyalkylene glycol (PAG)
14: A mercury bulb controller is not recommended for
- line or low voltage use
- line voltage use
- use where vibration is severe
- low voltage use
15: Where must a refrigeration contractor's license number be displayed?
- Truck, office, every job, and on all equipment
- Trucks, invoices, and advertising
- Uniforms, checks, and invoices.
- Trucks, license plates, and uniforms
16: If your suction line is warmer than the room temperature, this may indicate
- an over charge
- below normal superheat
- plugged air filter
- a low charge
17: Booster compressors, pump refrigerant into the
- heat & plate heat exchanges
- low side of the primary compressor
- high side of the secondary compressor
- receiver
18: While the system is operating, the discharge line should be
- too hot to hold by hand
- 10-15F warmer than ambient
- at the same temperature as the crankcase
- room temperature
19: 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.
- 100
- 80
- 110
- 90
20: "I" represents ____ in the Ohm's law formula.
- amperage
- capacitance
- resistance
- voltage.
21: Fusible plugs must have what marked on them?
- Melting temperature in F
- Melting temperature in C
- Opening pressure
- All of the above
22: A premise or that portion of a premise where large numbers of people congregate and from which occupants cannot quickly vacate the space such as auditoriums, ballrooms, classrooms, passenger depots, restaurants, and theaters is considered a(n)
- public assembly occupancy
- commercial occupancy
- illegal occupancy
- institutional occupancy
23: Refrigeration piping before being buried shall be
- leak tested
- encased in pipe duct
- pressure tested
- All of the above
24: Pressure is equivalent of
- Force
- Force / Area
- Area X Force
- Force X Area
25: What percentage of amperage difference is allowable phase to phase on a HVAC circuit phased to phase?
- 4%
- 1%
- 25%
- 2%