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HVAC S.T.A.R EXAM QUESTIONS AND ANSWERS
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HVAC S.T.A.R EXAM QUESTIONS AND ANSWERS
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HVAC S.T.A.R EXAM QUESTIONS AND ANSWERSThe evaporator in a refrigeration system: - Answers -Is the component where refrigerant
boils and absorbs heat.
The purpose of the compressor is to change ___________. - Answers -Low-pressure,
low-temperature vapor to a high-pressure, high temperature vapor
A common refrigerant leak detection device is the: - Answers -Halide torch.
Copper-plating of compressor parts is: - Answers -Caused by contaminants in the
system.
If not properly installed, a hot-gas muffler might trap: - Answers -Oil.
Unit ventilators are usually equipped with outside air dampers to: - Answers -A. Partial
Correct: Provide ventilation air during building occupancy
B. Partial Correct: Comply with most local or state codes
Face and bypass dampers should be adjusted to provide: - Answers -Tight shut off to
reduce the possibility of overcooling or overheating
With belt driven equipment, alignment of the motor and driven equipment pulleys -
Answers -Is accomplished using a string or straight edge.
To assist consumers in making an informed choice when purchasing unitary air
conditioning equipment, the efficiency of such units is expressed as Energy Efficiency
Ratio (EER or SEER) the units of which are: - Answers -Btuh/watt
Firestats located in the air stream of air handling units: - Answers -A. Partially Correct:
Are required in both the supply and return air streams
B. Partially Correct: Should be the manual reset type
C. Partially Correct: Should be nonadjustable
A sleeve bearing would typically be used in a motor that: - Answers -Operates with a
light load and where noise is a factor.
A bearing used on the bottom of a motor where the shaft is positioned vertically is called
a ____________ bearing. - Answers -Thrust
To produce electromagnetism, relative motion is required between a magnetic field and
a/an: - Answers -Conductor
Materials which do not allow their electrons to spin out of orbit easily are called: -
Answers -Insulators
, A battery is an example of a/an ____________ source. - Answers -Direct current
"Current flowing through a conductor in one direction for a split second, then in the
opposite direction for a split second" would be a good definition of: - Answers -
Alternating current
If a pressure gauge reads five psig at sea level elevation, the corresponding absolute
pressure is ___________ psia. - Answers -Fractional
The portion of the electromagnetic spectrum to which solar collectors respond is _____
and near-infrared radiation. - Answers -Visible light
During winter, ________. - Answers -Daylight is shorter and the Northern Hemisphere is
angled away from the sun
Unless equipped with OSHA or Canadian Standards Association (CSA) approved
ground-fault circuit interrupters, portable electric lighting used in wet and-or other
conductive locations as, for example, drums, tanks and vessels, shall be operated at
______ volts or less. - Answers -12
Receivers are usually required in systems having: - Answers -Evaporative condensers
An important feature of a refrigerant receiver, in the case where the liquid line to the
evaporator comes out of the top of the receiver, is a: - Answers -Dip tube
A pressure regulator is constructed so that a rise in ____________ steam pressure
reduces off the inlet flow of supply steam. - Answers -Downstream
A vacuum breaker is used to avoid which of the following - Answers -Negative gauge
pressure
Lock-out relays are used in air conditioning systems to: - Answers -Prevent compressor
short-cycling
When measuring the winding resistance of a split-phase compressor motor, the
smallest value will be measured between the: - Answers -The run terminal and the
common terminal
Cavitation in a pump pumping hot water: - Answers -A. Partial Correct: Makes a pump
noisy
B. Partial Correct: Is the result of water boiling into the steam
C. Partial Correct: Is the result of insufficient NPSH
The amount of heat removed to lower the temperature of 15 lbs. of water from 48
degrees F to 39 degrees F is: - Answers -135 Btu.
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