Topics: All categories in the pool
1: Halo-carbon refrigerants cannot be used with what material?
- Aluminum
- Magnesium alloy
- Copper
- Stainless Steel
2: What is the voltage of each leg of a 480 Volt three-phase motor?
- 240v
- 120v
- 208v
- 277v
3: Name an HCFC refrigerant(s):
- R-22
- R-123
- R-11
- both a & b
4: Usually dry bulb temperature is
- lower than dry bulb temperature
- same as wet bulb temperature
- not important and shall be ignored
- higher than wet bulb temperature
5: A normally operating R-410A system with a condensing temperature of 110F will have a high side pressure of around ______ psig
- 327 psig
- 255 psig
- 125 psig
- 365 psig
6: A water regulating valve opens when
- the compressor is on
- when the power is on
- when the power is on there is an overcharge of refrigerant
- the head pressure rises
7: Pressure vessels with an internal volume of 3 cubic feet or more
- shall use pressure relief devices
- shall use pressure relief devices or fusible plugs
- do not need pressure relief protection
- shall use fusible plugs
8: Large Mercantile occupancy is a premise or that portion of a premise where more than ____ persons congregate on levels above or below the street level to purchase personal merchandise.
- 350
- 400
- 250
- 100
9: Class T machine room
- shall have remote controls to stop the action of the refrigerant compressor
- shall include closets used for setting equipment
- has no flame producing apparatus permanently installed
- shall have refrigerant leak detecting systems installed inside and outside the room
10: "I" represents ____ in the Ohm's law formula.
- voltage.
- resistance
- amperage
- capacitance
11: What device should be used on low-temperature freezers?
- oil separator
- discharge muffler
- high capacity TXV
- hot-gas by-pass
12: In an air conditioning plant which an indirect low side, water is used inside of bring: the proper sequence of operating the plan is
- reset the safety valve
- start the fan and circulating pump
- start the comrpessor
- reset the expansion valve
13: A capacitor in series with the start windings will do what?
- Nothing
- Decrease the RLA to within 10% of its rating
- Increase starting torque
- Increase run efficiency by 10% of its rating
14: The outer portion of shell of the compressor used on low-pressure chillers is called the
- nozzle
- volute
- suction
- baffle
15: Group A2 refrigerants have a ______ toxicity rating than Group B1 refrigerants.
- the same
- lower
- higher
- there is no Group B1 refrigerants
16: When the compressor is below the condensor
- traps are needed on the suction line
- traps are needed on the discharge line
- traps are not needed on this type of system
- traps are needed on the oil return line
17: The first step in mechanical refrigeration is
- compression
- expansion
- condensation
- evaporation
18: 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
19: The level of voltage caused by back electromagnetic force that opens the contacts of a potential relay in order to take the start capacitor out of the circuit is
- pick up voltage
- boost voltage
- run voltage
- lift voltage
20: Refrigeration piping before being buried shall be
- leak tested
- encased in pipe duct
- pressure tested
- All of the above
21: If a low-pressure chiller has a low-side leak, which of the following will most likely result?
- High head pressure and low suction pressure
- Low head pressure and high suction pressure
- Low suction pressure and low discharge pressure
- High suction pressure and high discharge pressure.
22: 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
23: If the suction pressure is low and the evaporator temperature high, the cause will be a?
- starved evaporator
- overcharged
- too small evaporator
- compressor suction valve stuck open
24: What is the minimum size wire you can use on a 30 amp circuit?
- 10 AWG
- 16 AWG
- 12 AWG
- 14 AWG
25: There can be no airflow from an occupied space through a machine room unless what?
- System is high velocity
- System is ducted and sealed
- Duct is not located in the ceiling
- None of the above.