Topics: All categories in the pool
1: Two capacitors are wired in parallel. One capacitor has a value of 15uf. The other has a value of 25uf. What is the total value supplied?
- 20 uf
- 25 uf
- 40 uf
- 15 uf
2: A relief valve shall be located at least ___ above grade.
- 25'
- 10'
- 15'
- 36'
3: The heat picked up in the evaporator must equal to
- the heat giving by the condenser
- the heat gained by the condenser
- the heat lost by the medium being cooled
- the heat of compression
4: The rupture disc on a low-pressure chiller typically releases pressure at
- 0 psig
- 10 psig
- 15 psig
- 5 psig
5: Instead of using a compressor, an absorption air-conditioning chiller uses which of the following as its driving force?
- Oil
- Electricity
- Heat
- Air
6: If the dry bulb temperature is 85F and the wet bulb temperature is 70F, the dew point temperature will be approximately (use psychometric chart)
- 32F
- 58F
- 70F
- 77F
7: What are the three components of a transformer?
- Primary core, secondary coil, and high and low voltage connectors.
- Contacts, secondary coil, and core
- Primary coil, secondary coil, and core
- Primary coil, secondary coil, and copper contacts
8: A tachometer is an instrument used to measure
- air velocity
- static pressure
- speed
- RPM
9: 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 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
- 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
10: Liquid refrigerant R-22 enters an evaporator at 50.2 psig, 20F and leaves 37F, its pressure as it leaves will be
- 43.3 psig
- 70.8 psig
- 50.2 psig
- 66.1 psig
11: A normally operating R-410A system with a condensing temperature of 110F will have a high side pressure of around ______ psig
- 125 psig
- 255 psig
- 365 psig
- 327 psig
12: How many CFMs are required per square foot of commercial office occupied space
- .5 CFM
- 15 CFM
- 5 CFM
- 20 CFM
13: Setting a pressure relief device shall not exceed ___ of the design pressure
- 75%
- 80%
- 90%
- 100%
14: An example of an "Expendable Refrigerant" is
- liquid nitrogen
- lithium bromide
- liquid oxygen
- ammonia
15: Before replacing a seized compressor, the _______ should be determinded.
- type of refrigerant
- designed head pressure
- cause of seizure
- current draw
16: Refrigerant is metered into the evaporator on a large centrifugal chiller thru the
- low side of the system
- high side float assembly
- cap tube
- none of the above
17: Can ammonia be used on domestic system?
- yes
- no, unless there is proper ventilation system installed
- no
- yes, for systems under 10 tons
18: Low pressure chiller systems use what type of compressor?
- Scroll
- Reciprocating
- Screw
- Centrifugal
19: R-22 is considered a(n)
- HCFCH
- CFC
- HFC
- HCFC
20: Dew point is
- the temperature below which water vapor in the air will start to condense
- the temperature of air of 50% RH
- the temperature below which water vapor in the air will start to evaporate
- the temperature above which water vapor in the air will start to condense
21: Name an HCFC refrigerant(s):
- R-22
- R-123
- R-11
- both a & b
22: If a refrigerant leaving the condenser is 94F and the condensing temperature is 105F, the subcooling is
- 29F
- 11F
- 21F
- 9F
23: Which refrigerant class listed below is the most flammable?
- C3
- A2
- B2
- A3
24: What is the temperature that a liquid and a vapor can exist in equilibrium called?
- Wet bulb temperature
- Dry bulb temperature
- Critical temperature
- Saturated temperature
25: An example of direct system is
- rooftop unit
- chiller
- absorber
- none of the above