Topics: All categories in the pool
1: The density of a gas refers to
- cubic feet per pound
- pounds per square foot
- pounds per absolute pressure
- pounds per cubic foot
2: In a properly balanced system with valves open and properly adjusted, if the suction line is warm to the touch, its because of
- oil in evaporator
- moisture in the system
- not enough oil in the system
- low head pressure
3: The purpose of an accumulator is to
- filter out impurities from the system
- assure no liquid returns to the compressor
- reduce friction loss to the flow of refrigerant
- store excess refrigerant from the reciver
4: Volts x amps equals
- Ohms Law
- Impedance
- Watts
- Inductance
5: What is absolute humidity?
- the amount of moisture in the air per one pound of 50% RH air
- the amount of moisture in the air in grains of cubic feet of volume
- the amount of moisture in the air in grains of square feet of volume
- none of the above
6: Watt's Law indicates Volts X Amps = _________.
- Current
- Watts
- Ohms
- Resistance
7: Two systems using separate refrigerants that are superimposed upon one another is called
- booster
- single stage
- indirect
- cascade
8: Group A2 refrigerants have a ______ toxicity rating than Group B1 refrigerants.
- the same
- there is no Group B1 refrigerants
- higher
- lower
9: When a pressure gauge is permanently installed on a system, it must be ___ times the design pressure of the system.
- 1
- 1.5
- 1.2
- 2.2
10: A chilled water pump's suction gauge reads 10 psig. The discharge gauge reads 48 psig. What is the head in feet the pump is working against?
- 58
- 88
- 38
- 96
11: 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
12: A crankcase heater has a supplied voltage of 100 volts and is drawing 1.4 amps. What is the resistance?
- 80 ohms
- 71 ohms
- 104 ohms
- 27 ohms
13: What do you need to do when you install a new system?
- Insulate the suction line before you take a superheat reading
- Have it inspected
- Add refrigerant
- Document the superheat and subcooling reading
14: What is the typical air conditioning operating pressures for 410A?
- 60 psi suction, 210 psi discharge
- 25 psi suction, 125 psi discharge
- 105 psi suction, 350 psi discharge
- None of the above
15: When can 50/50 solder be used?
- in the low side
- in the high side
- liquid and suction lines
- none of the above.
16: When the compressor is below the condensor
- traps are not needed on this type of system
- traps are needed on the suction line
- traps are needed on the discharge line
- traps are needed on the oil return line
17: A hissing noise at the expansion valve is a good indication that
- nothing is passing thru
- liquid is passing thru it
- expansion valve is oversized
- gas is passing thru it
18: Thermodynamics is the branch of science that deals with
- state of energy
- molecular therory
- heat energy
- energy due to motion
19: Pressure vessels with an internal volume of 10 cubic feet or more
- shall use pressure relief devices or fusible plugs
- shall use pressure relief devices
- shall use rupture discs or duel pressure relief valves
- shall use fusible plugs
20: The Department that certifies the transportation of refrigerant is the
- DOT
- RSES
- EPO
- EPA
21: The gauge thickness required on a CO2 tank construction is
- 1/16"
- 5/16"
- 3/32"
- 1/8"
22: A chiller entering and leaving temperature difference is?
- 50 degrees F
- 20 degrees F
- 5 degrees F
- 10 degrees F
23: 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
24: What refrigerant were phased out in 2004?
- R-134a
- R-12
- R-22
- R-11
25: How does a centrifugal compressor create the pressure differential needed to move refrigerant through the system?
- Rotating vanes
- Nesting scrolls
- Fan-like action
- Suction and discharge valves