HVAC BOMA Pre-Quiz (website). Exam
Questions With Correct Answers
Two basic categories of chillers are the _____. - answer✔✔Compression cycle and absorption
The five requirements for comfort are proper temperature, humidity, filtration, _____. -
answer✔✔Circulation
The primary function of an expansion device is to _____. - answer✔✔All of the above (produce
a reduction in the pressure on the liquid refrigerant, regulate the flow of refrigerant into the
evaporator and lower the boiling point of the refrigerant far enough below the temperature of the
load to get the needed heat transfer rate.
The wet-bulb depression is _____. - answer✔✔The difference between the dry-bulb and wet-
bulb temperatures.
The dew-point temperature is the _____. - answer✔✔Temperature when the moisture begins to
condense out of the air.
How many Btu are required to change one pound of ice at 20°F to steam at 220°F -
answer✔✔1,304 Btu/h
If an R-12 refrigeration system is operating with a 25.4 psig suction pressure, what is the
evaporator superheat if the evaporator outlet temperature is 34°F - answer✔✔9
On an R-11 or R-123 system, the refrigerant removal process normally starts with the removal of
_____. - answer✔✔Liquid refrigerant
The condenser in a refrigeration system _____. - answer✔✔All of the above (desuperheats the
vapor from the compressor, condenses the vapor from the compressor and subcools the liquid
refrigerant before it leaves the condenser)
The human body gives off heat by which of the following? - answer✔✔All of the above
(convection, radiation and conduction)
If the temperature remains constant and the volume that a gas occupies increases, the pressure
will _____. - answer✔✔decrease
Transformers are rated using _____. - answer✔✔Volt-amperes
A solid material exerts a pressure or force _____. - answer✔✔Downward only
Pure water boils at temperature of 213°F, at which of the following standard conditions? -
answer✔✔14.967psi
Which of the following would allow a system to operate more efficiently? -
answer✔✔Condenser that had refrigerant leaving with 15°F of subcooling
One watt of electrical energy is equal to _____. - answer✔✔3.413 Btu
Rotary compressors are used primarily in _____. - answer✔✔Domestic refrigerators
The water circuit in shell and coil and coil-type tube-in-a-tube condensers must be cleaned
_____. - answer✔✔Chemically
When a water regulating valve is used to control the head pressure of the water-cooled system,
the valve's spring is acting against which pressure to modulate the waterflow? - answer✔✔Head
pressure of the system
The standard atmospheric pressure at sea level is _____. - answer✔✔29.92"
The steps to aggressively controlling the contamination of indoor air would involve _____. -
answer✔✔All of the above (locating and eliminating the source of contamination, providing
adequate ventilation and providing methods for cleaning the air)
If the resistance against a propeller fan is doubled, the cfm output decreases, but the amperage
draw of the motor _____. - answer✔✔Increases
Which of the following re-presents a different temperature than the other three? -
answer✔✔475K
The best method of leak checking is when the refrigeration system is _____. -
answer✔✔Standing with dry nitrogen pressure of 150 psig in the system
Technician "A" says that if the air filter on an air-conditioning system is totally blocked with
dirt, the amperage draw of the evaporator fan motor will go down. Technician "B" says that if
you close down one supply register on a duct system, the volume of air feeding the other
locations will increase slightly. Which of the following statements is correct? -
answer✔✔Technician "A" is correct. Technician "B" is correct.
The refrigerant in a refrigeration system changes state in the _____. - answer✔✔Condenser and
evaporator
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