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55 Cards in this Set
- Front
- Back
Hot water heating systems produce heat more consistently than steam heating systems.
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True
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Hot water heating systems require less water than steam heating systems.
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False
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The natural circulation hot water heating system uses circulating pumps to transport water in the system.
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False
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Water becomes less dense as it is heated.
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True
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The natural circulation hot water heating system uses a compression tank to absorb pressure changes.
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False
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Natural circulation hot water heating systems are commonly used in large contemporary buildings.
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False
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Floor-mounted circulating pumps are used in small plants.
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False
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Line-mounted circulating pumps operate intermittently, depending on plant requirements.
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True
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The forced circulation hot water heating system is vented to the atmosphere.
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False
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The aquastat controls the starting and stopping of the burner on a hot water boiler.
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True
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The flow control valve prevents natural circulation when water is not pumped in the forced circulation hot water system.
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True
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The pressure-reducing valve is used to prevent overpressure of water supplied to the expansion tank.
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False
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Diverter fittings are used to vent air from the heating units.
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False
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Stop valves before and after the pressure-reducing valve allow servicing of the pressure-reducing valve.
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True
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The three-way mixing valve blends water returning from the heating units with supply water from the boiler.
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True
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All boilers are manufactured in conformance with Section I or IV of the ASME Boiler and Pressure Vessel Code.
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True
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An aquastat controls the burner by sensing steam pressure in a hot water boiler.
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False
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The strainer in the pressure-reducing valve should be inspected periodically for scale formation.
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True
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The compression tank is normally full of water to feed into the boiler during a low water condition.
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False
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The relief valve should be located on the highest part of the boiler.
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True
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Relief valves should be manually tested every 30 days as recommended by the ASME Code.
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True
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Relief valves should discharge into the return line feeding into the circulating pump.
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False
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A temperature-pressure gauge indicates temperature in the compression tank.
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False
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Hydrostatic pressure is expressed in pounds per square inch (psi).
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True
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Air controls are used to allow water to drain from the compression tank.
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False
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Air removed from the boiler water is diverted to the compression tank in a forced circulation hot water heating system.
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True
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An aquastat commonly has a temperature differential preset by the manufacturer.
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True
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The aquastat temperature differential setting controls the starting and stopping of the circulating pump.
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False
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Two diverter fittings may be required for heating units above the supply line where resistance to circulation is high.
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True
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Hot water heating systems require special hot water boiler accessories.
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True
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Water conveys approximately one-___ the amount of heat that steam conveys.
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fifth
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A hot water heating system operates at ___ the steam heating system.
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a lower temperature than
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In a natural circulation hot water heating system, the ___ functions as a relief valve.
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expansion tank
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___ pressure is water pressure per vertical foot exerted at the base of a column of water.
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Hydrostatic
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In a remote temperature-monitoring system, the burner is controlled based on ___.
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outside temperature
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Steam boilers are classified as "high pressure" if steam pressure exceeds ___ psi.
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15
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A flow control valve functions similarly to a(n) ___ valve to prevent natural water circulation.
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check
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Hot water boilers operating with a 250°F water temperature and ___ psi water pressure or less are classified as low pressure.
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160
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Hot water boilers can be ___ boilers.
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firetube, watertube, & cast iron sectional
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A hot water boiler relief valve is rated in ___ relieved per hour.
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BTU's
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A steam boiler safety valve is rated in ___ relieved per hour.
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pounds of steam
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A relief valve must be built according to the ___.
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ASME Code
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The relieving pressure of a relief valve on a low pressure hot water boiler cannot exceed ___ psi.
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160
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The two types of low water fuel cutoffs normally used on hot water boilers are the ___-type and the probe-type cutoffs.
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float
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The ___ tank is normally half full of water to maintain the correct water level in the forced circulation hot water heating system.
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compression
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Section VI of the ASME Code recommends relief valves be manually tested ___.
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every 30 days
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The ___ protects the hot water heating system from exceeding the MAWP.
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relief valve
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The ___ controls the starting and stopping of the burner by sensing the temperature in the hot water boiler.
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aquastat
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The temperature-pressure gauge indicates the temperature and pressure of the water ___.
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leaving the boiler
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___ direct the flow of hot water supplied to and returned from the heating units.
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Diverter fittings
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A ___ prevents natural circulation when hot water is not being pumped through the forced circulation hot water system.
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flow control valve
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A pressure-reducing valve reduces the pressure of city water to approximately ___ psi.
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12 to 18
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A(n) ___ allows bleeding of trapped air in a heating unit.
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air vent
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If the compression tank is allowed to fill with water, pressure will increase, causing the ___.
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relief valve to open
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Larger compression tanks are equipped with a ___ for determining the compression tank water level.
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gauge glass
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