Frage 1
Frage
If properly designed, a closed-loop hydronic system should rid itself of most air within a few days of initial start-up.
Frage 2
Frage
The oxygen that causes corrosion is the same oxygen that forms water molecules.
Frage 3
Frage
Circulators transfer maximum head energy to incompressible fluids (e.g., liquids). A mixture of water and air is an example of an incompressible fluid.
Frage 4
Frage
Air has much lower specific heat and density than water.
Frage 5
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Circulators with internal spring-load check valves installed in vertical piping with upward flow are especially susceptible to air pockets.
Frage 6
Frage
Although water may appear perfectly clear and free of bubbles, it can still contain a significant quantity of air in solution.
Frage 7
Frage
Combined air and dirt separators, or a hydraulic separator with the same capabilities, are never desirable in situations where an older distribution system containing steel or iron piping or radiators will be interfaced to a new boiler.
Frage 8
Frage
Properly designed and installed hydronic systems will always require constant manual air venting.
Frage 9
Frage
Low system pressurization is usually caused by not setting the make-up water system properly.
Frage 10
Frage
Glycol-based antifreezes tend to leave a slippery film on components and tools that eventually turn sticky.
Frage 11
Frage
Flow noise is generated when dissolved gases are released from improperly deaerated fluid due to a __________ in pressure.
Antworten
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increase
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modulation
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equalization
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reduction
Frage 12
Frage
Air contains oxygen, and oxygen in contact with ferrous metals creates __________.
Antworten
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oxides
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antigens
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bubbles
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deaeration
Frage 13
Frage
A large pocket of air trapped within a system can totally stop flow. This effect is often called air _________.
Antworten
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blockage
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plugging
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binding
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trapping
Frage 14
Frage
Dissolved air can also lead to gaseous cavitation. Gaseous cavitation occurs when the pressure on the fluid __________ the saturation pressure of the dissolved gases it contains.
Antworten
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equals
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drops below
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rises above
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is double
Frage 15
Frage
When air exists as bubbles, a moving fluid may be able to carry them along through the system. This is called __________ air.
Antworten
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entrained
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fluid
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deaerated
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bubbly
Frage 16
Frage
The air removal devices used in small hydronic systems can be classified as either high point vents or __________.
Antworten
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"bleeders"
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central air separators
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"coin vents"
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deaerators
Frage 17
Frage
The need for fully automatic (unattended) venting in locations not easily accessed requires a different type of device. A(n) __________ air vent often provided the solution.
Antworten
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electronic
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top-loaded
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ergonomic
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float-type
Frage 18
Frage
A(n) __________ is capable of maintaining the system fluid in an unsaturated state of air solubility. This means that the water is always ready to absorb additional air from any areas of the system where it may be present.
Frage 19
Frage
A device that makes short work out of filling and purging residential and light commercial hydronic systems consists of a minimum 1-horsepower swimming pool pump mounted on a 30-gallon plastic trash barrel. This device is called a(n) __________.
Antworten
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circulator
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purge cart
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air scooper
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deaerator
Frage 20
Frage
An automatic fluid feeder uses a small positive displacement pump operated by a pressure sensing switch to automatically pump fluid into the system when the pressure __________ a set minimum value.
Antworten
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reaches
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drops below
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exceeds
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is stored at