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HVAC Pretest BOMAexam questions with 100- correct answers
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HVAC Pretest BOMAexam questions with 100- correct answers
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HVAC Pretest BOMAexam questions with 100- correctanswers
The purpose of an externally equalized thermostatic expansion valve is to ____.
a. compensate for excessive evaporator pressure drop
b. allow system to equalize faster
c. prevent the expansion valve from frosting up
d. allow refrigerant to expand in the compressor - ✔✔ANSW✔✔..a. compensate for
excessive evaporator pressure drop
The pressure in a duct system is measured in:
a. psig
b. psia
c. " Hg
d. " WC - ✔✔ANSW✔✔..d " WC
If the compression ratio of a system with a reciprocating compressor decreases, the
amount of refrigerant pumped by the compressor ____.
a. will increase
b. will decrease
c. will remain the same
d. cannot be determined - ✔✔ANSW✔✔..a will increase
The approach of a cooling tower is the ____.
a. difference between the entering and leaving wet-bulb temperatures
b. number of degrees the water is cooled in the tower
c. difference in temperature between the entering air wet-bulb temperature and the
sump water temperature
d. difference in temperature between the entering air web-bulb temperature and the
water entering the tower - ✔✔ANSW✔✔..c difference in temperature between the
entering air wet-bulb temperature and the sump water temperature
,The screw-type compressor is used primarily in ____.
a. large industrial refrigeration and air-conditioning systems
b. residential air conditioning
c. small commercial refrigeration units
d. domestic refrigerators - ✔✔ANSW✔✔..a. large industrial refrigeration and air-
conditioning systems
At what location or locations in a refrigeration system does the saturation pressure
correspond to the saturation temperature?
a. compressor and evaporator
b. evaporator and condenser
c. condenser and expansion device
d. compressor - ✔✔ANSW✔✔..b evaporator and condenser
A split-phase motor can use a ____ to energize and de-energize the start winding.
a. potential relay
b. current relay
c. centrifugal switch
d. all of the above - ✔✔ANSW✔✔..d. all of the above
Temperature is an indication of the ____.
a. amount of heat in a material
b. density of the material
c. amount of molecular activity in the material
d. weight of the total mass of the material - ✔✔ANSW✔✔..c. amount of molecular
activity in the material
The compressor motor and condenser fan motor are wired in ____.
a. parallel
b. series
c. parallel/series
d. with minimum wire length - ✔✔ANSW✔✔..a. parallel
How many watts of electrical power are equal to 1 horsepower?
a. 33000
b. 15000
c. 746
d. 660 - ✔✔ANSW✔✔..c. 746
, How many Btu's are required to change five pounds of ice at 20°F to steam at 220°F?
a. 1,304 Btu/h
b. 2,608 Btu/h
c. 6,520 Btu/h
d. 3,912 Btu/h - ✔✔ANSW✔✔..c. 6,520 Btu/h
Refrigeration can be described as ____.
a. the process of making products cold
b. the process of introducing heat to a location where it is not wanted
c. the process of removing heat from a place where it is not wanted to a place where it
makes little or no difference
d. none of the above - ✔✔ANSW✔✔..c. the process of removing heat from a place
where it is not wanted to a place where it makes little or no difference
Two basic categories of chillers are the ___.
a. Compression cycle and absorption
b. purge and absorption
c. absorption and lithium bromide
d. purge and lithium bromide - ✔✔ANSW✔✔..a. Compression cycle and absorption
The five requirements for comfort are proper temperature, humidity, filtration, _____,
and ventilation.
a. circulation
b. velocity
c. sq.ft.
d. none of the above - ✔✔ANSW✔✔..a. circulation
The primary function of an expansion device is to ____.
a. produce a reduction in the pressure on the liquid refrigerant
b. regulate the flow of refrigerant into the evaporator
c. lower the boiling point of the refrigerant far enough below the temperature of the load
to get the needed heat transfer rate
d. all of the above - ✔✔ANSW✔✔..d. all of the above
The wet-bulb depression is ____.
a. the difference between the dry-bulb and wet-bulb temperatures
b. the same as the wet-bulb temperatures
c. the same as the dry-bulb temperatures
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