Topics: All categories in the pool
1: Which of the following is an example of an azeotropic refrigerant?
- R-410A
- R-404A
- R-500
- R-134A
2: Brazed joints melt at temperatures above
- 500F
- 1,200F
- 1,000F
- 800F
3: A factory-sealed system containing less than 22lbs. of Group A1 refrigerant
- shall be inspected by the Boiler of Inspectors bi-annually
- shall have a pressure limiting device installed on the high side of the system
- does not require a pressure-limiting device
- shall have a pressure limiting device and a pressure relief valve installed
4: Which refrigerant was still able to be vented to the atmosphere after July 1, 1992?
- R-22
- R-11
- R-12
- R-113
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: What effect does the temperature of air have on humidity?
- warmer air holds more moisture then cooler air
- cooler air holds more moisture then warmer air
- air has no effect of humidity
- none of the above
7: Color is important in oil because
- it indicates the viscoisty.
- can tell us something about the refining of oil
- it makes sight glasses easy to read
- allows you to see into crankcase
8: What does safe access mean?
- Locked doors
- A clear unobstructed path to the equipment and controls
- Well-lit exit signs
- OSHA approved
9: Can ammonia be used on domestic system?
- yes
- no, unless there is proper ventilation system installed
- no
- yes, for systems under 10 tons
10: When can recovered refrigerants be reused?
- They can't
- Only when used in original owner's equipment
- Only if used in 30 days of recovery
- None of the above
11: High side floats are used on centrifugal chiller systems are are considered critically charged systems.
- are obsolete.
- True
- False
- depends on the type of refrigerant being used
12: Crankcase heaters are energized
- to prevent compressor freeze-up
- while the compressor is running
- when the compressor is off
- to allow easy compressor start-up
13: Where would the EPR valve be located on a multiple evaporator system?
- outlet of high temperature evaporator
- outlet of the liquid line
- inlet of the low temperature evaporator.
- outlet of low temperature evaporator
14: Before replacing a seized compressor, the _______ should be determinded.
- type of refrigerant
- designed head pressure
- cause of seizure
- current draw
15: Transformers are rated in
- volts
- amps
- volt-amps
- volts-ohms
16: Suction valve unloaders afford an effective means of
- evaporator control
- capacity control
- superheat control
- refrigerant control
17: How far from the window does a relief valve need to be according to ASHRAE-15?
- There is no minimum for relief valve and windows.
- At least 20'
- At least 40'
- At least 30'
18: What measures gas pressure?
- Manometer
- Hygrometer
- Barometer
- Hydrometer
19: The location of a thermal bulb of a TXV affects
- subcooling
- the amount of liquid in the condenser.
- the amount of liquid returning to the compressor
- the amount of liquid refrigerant in the evaporator
20: System design pressures must take into consideration, not only, pressures found during normal operation but also what?
- When it's cold out
- When there is a malfunction on the high side
- When its warm out
- All of the above
21: Low ambient controls are used when
- when systems run all year round
- economizers are used
- always
- on air conditioning systems only
22: If a purge unit fails on a low pressure chiller, what are the symptoms?
- increased capacity
- low pressure chillers do not have purge units
- high head pressure
- low suction pressure
23: When is the only time you can leave a service container attached to a system?
- Leaking system
- Recovery
- Charging
- Both b and c
24: If a halide torch is used for leak detection, what color is the flame if it detects a leak?
- blue
- red
- green
- orange
25: The first step in mechanical refrigeration is
- evaporation
- condensation
- expansion
- compression