Topics: All categories in the pool
1: Heat transferred by conduction from one body to another is done
- via solids
- via liquids
- via heat rays
- via radiation
2: What is the boiling point of refrigerant governed by?
- Compressor RPM's
- P&T relationship
- Condenser sub-cooling
- Evaporator temperature
3: Trichlorofluoromethane is the name of what refrigerant?
- R-502
- R-11
- R-113
- R-12
4: The test pressure applied to the high side of each factory-assembled refrigerating system shall be at least equal to the design pressure of
- the low side
- the high side
- the aggregate of the high side and low side
- 2.5 times the design pressure
5: Ammonia (NH3) is a group III refrigerant
- True
- False
6: Name a reason that does not cause reduced condenser air quantity
- Prevailing winds
- Dirty Coil
- High ambient temperature
- Dirty fan blades
7: What is considered a cooling agent?
- 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 without vaporization
- any liquid used for the transmission of heat when condensation occur
8: On a pumpdown system, the liquid-line solenoid is controlled by the
- low-ambient controller
- thermostat
- defrost timer
- low pressure switch
9: Sensible heat is the heat added to a substance to
- cause evaporation
- change its state
- raise its temperature
- freeze it
10: What is the voltage of each leg to ground of a three-phase motor with a 460v supply voltage?
- 208v
- 277v
- 240v
- 120v
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: On a large centrifugal system, what meters the flow to the evaporator?
- TXV
- Cap tube.
- Low side float
- High side float
13: What must be done to refrigerant pipes before being buried ?(8.10.4)
- Leak checked
- Certified
- Insulated and installed in a pipe duct (Encased)
- Classifed
14: Which occupancy can ammonia be used in?
- depends on the quantity of freon
- redifential
- industrial
- commercial
15: When should a relief valve start to function?
- Before the purge station discharges
- Two times it's working pressure
- At it's set pressure
- 10 psi before it's set pressure
16: The density of a gas refers to
- pounds per absolute pressure
- cubic feet per pound
- pounds per square foot
- pounds per cubic foot
17: When using nitrogen for brazing, the pressure should be:
- Very low
- Slightly below atmospheric
- 125 psig
- 50-100 psig
18: What is NOT a positive displacement compressor.
- Scroll
- Rotary
- Reciprocating
- Centrifugal
19: Aluminum, Zinc, Magnesium, or their alloys shall not be used in contact with
- methyl chloride
- trichlorotrifluoromethane
- ammonia
- R-718
20: What is Absolute Zero?
- -400F
- -773F
- -460F
- -640F
21: 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
22: A positive displacement compressor is
- a compressor in which the increase in pressure is attained by changing the internal volume of the compression chamber
- where the compressor's suction pressure and the compressor;s discharge pressure is more than 50 PSI
- a compressor in which the increase in pressure is attained by changing the internal pressure of the compression chamber
- is a reciprocating type compressor with 2 or more pistons
23: How many gallons of water per pound of ammonia do you need?
- 20
- 5
- 1
- 15
24: What type of oil is used in R-410A systems?
- mineral oil
- naphthene
- polyalkylene glycol (PAG)
- polyolester (POE)
25: A motor starter contains a thermal overload and a
- transformer
- 3-way relay
- contactor
- solenoid