(4-128-1.1) Which of the following is an advantage of medium and high pressure HVAC duct systems?
Select one:
a. Lower operating cost
b. No need for
... [Show More] costly noise suppression devices
c. Less costly fabrication and installation
d. Less physical space requirements - ✔✔ D
(4-130-1.7) Steam coils with a short tube length of 1.1 m or less, in comparison to steam coils with long tube lengths,
Select one:
a. are more likely to freeze, even if the steam trap is properly chosen
b. require two preheat coils to prevent freeze-up.
c. must use two-position steam valves to prevent freeze-up.
d. are less likely to freeze if the steam trap is properly chosen and the coil is properly piped. - ✔✔ D
(4-127-1.3) Air duct velocity pressure is measured by connecting a:
Select one:
a. Manometer to the side of an air duct
b. Bourdon tube to the air duct
c. Pressure gauge to the side of a duct, with a sensing tube extending inside of the duct directed toward the airflow
d. Manometer to the side of a duct, with a sensing tube extending inside of the duct directed toward the airflow - ✔✔ D
(4-128-3.4) Calculations of return air duct leakage include:
Select one:
a. 3% seepage if the return air duct is located outside the conditioned space.
b. 3% seepage if the return air duct is located both inside and outside the conditioned space.
c. 10% leakage if the return air duct is located inside the conditioned space.
d. 3% leakage if the return air duct is located inside or outside the conditioned space. - ✔✔ A
(4-102-3.6) Viscous impingement filters are highly efficient in the removal of:
Select one:
a. Fine dust, fumes, and smoke
b. Bacteria and spores
c. Cooking odours
d. Dust and pollen - ✔✔ D
(4-130-1.5) To prevent freezing of a steam coil, when steam pressure at the coil inlet is too low:
Select one:
a. A second preheat coil must be installed at the outside air inlet.
b. A two-position steam control valve must be installed at the coil inlet.
c. The supply air fan is stopped and the outside air dampers are shut.
d. Inverted bucket steam traps must be used. - ✔✔ C
An air filter capable of removing particles as small as 0.3 micron in diameter with 99% efficiency is a
Select one:
a. a HEPA filter.
b. an odour absorber.
c. a charged-media air cleaner.
d. a viscous impingement filter. - ✔✔ A
(4-130-4.4) With respect to steam trap installations, which of the following statements is FALSE?
Select one:
a. Choose a steam trap based on the pressure difference across the trap, and a minimum capacity corresponding to three times the coil condensate rate.
b. Locate the steam trap so that its outlet is at least 30 cm above the coil condensate outlet.
c. Trap each steam coil separately.
d. Drip the steam supply main through a steam trap into the return condensate main, and not through the steam coil. - ✔✔ B
(4-130-4.2) Modulating control valves:
Select one:
a. Are mainly used for steam coils when the entering air temperature is below 1.5°C.
b. Are used for steam coils where the condensate must be lifted to an overhead condensate return line.
c. Can successfully control steam coils, as long as the air entering the coil is at or above 1.5°C .
d. Should be over-sized to prevent steam coil freeze-up.
e. Are never used to control steam coils, regardless of inlet air temperature. - ✔✔ C
(4-130-4.3) The inverted bucket steam trap, as applied to steam heating coils,
Select one:
a. Is used when the coil steam pressure is higher than 172 kPa or 25 psig
b. Is used when considerable air venting is required.
c. Does not require a strainer.
d. Is recommended when condensate flows by gravity into a return main at atmospheric pressure. - ✔✔ A
(4-127-2.6) The two general groups of fans are:
Select one:
a. Positive displacement and dynamic
b. High volume and low volume
c. Positive displacement and axial flow
d. Centrifugal and axial flow - ✔✔ D
(4-102-3.4) Ultraviolet light is used to remove _____ from the air.
Select one:
a. Dust and pollen
b. Fine dust and smoke
c. Bacteria
d. Mists and fogs - ✔✔ C
(4-131-3.2) Air washers can achieve dehumidification when
Select one:
a. the water temperature is greater than the dry bulb temperature.
b. the spray water is cooled to below the dew point.
c. the return air is more humid than the outside air.
d. the specific humidity of the air is greater than the relative humidity. - ✔✔ B
(4-131-2.1) Humidifying units that force warm air through a wet pad, and return the air to the room, are called:
Select one:
a. Pan type humidifiers with plates
b. Atomizing humidifiers
c. Bypass type humidifiers
d. Wetted element humidifiers - ✔✔ D [Show Less]