Start what?
In open systems, static pressure on the discharge side of a pump is balanced by static pressure on the station side. True/False
False
In the adjustment of individual outlets or terminals, any restriction built up by adjusting the volume control dampers at one outlet may significantly decrease the flow through adjacent outlets. True/False
False
Initial checks and tests for proper and safe operation should be made immediately before start-up. True/False
False
Instruments measuring for duct air pressures, which are relatively low pressures, usually measure in unit inches of mercury. True/False
False
Matter is any substance that occupies space and has no weight. True/False
False
Medium-duty pulleys are rated for 75hp to 150hp. True/False
False
Moist air in a three-component mixture of dry air, water vapor, and smoke. True/False
False
Most manometer scales read ounces of water. True/False
False
Net positive suction head is normally not a consideration in open systems. True/False
False
Pressure below atmospheric pressure is usually referred to as impact pressure. True/False
False
Since mercury weighs 13.6 times as much as water, it will move 13.6 times the distance that water would move at a given pressure. True/False
False
Static pressure values are fairly high pressures and should be measured with the static tube of a Pitot tube and a gauge, such as a digital thermometer. True/False
False
Static pressure varies inversely with density. True/False
False
Test pressure is typically 85% to 100% of operating pressure. True/False
False
The brake horsepower actually required to drive a pump is less than the theoretical water horsepower by an amount equal to the inefficiencies in the pump. True/False
False
The calibration data for an orifice insert without a differential pressure gauge is furnished on the nameplate, which indicates the flow rate in CFM for the pressure drop as measured. True/False
False
The cooling of air usually involves the removal of moisture without a change in DB temperature. True/False
False
The direction and amount of deflection of grills and registers do not have an effect on throw and spread. True/False
False
The liquid in a liquid-in-glass thermometer is usually mercury or lead. True/False
False
The relative humidity of dry air is 100%. True/False
False
The speed of a turning wheel or shaft is usually determined in revolutions per hour. True/False
False
The term "flow coefficient," or "valve constant," is the flow rate in GPM that will cause a pressure a pressure drop of 2.31 PSI, 1 ft. of water, across a valve. True/False
False
The vertical portion of an inclined-vertical manometer gives it the ability to measure higher pressures, such as up to 12 or 15 in.w.g., in a compact instrument. True/False
False
Three basic types of air supply outlets are grilles, slot diffuser outlets, and floor diffusers. True/False
False
To determine chiller capacity, read and record water temperatures entering and leaving a cooling water tower and the dry bulb (DB) and wet bulb (WB) temperatures of the ambient air. True/False
False
Two-position type damper control provides gradual opening and closing of a damper. True/False
False
When a pump is field tested, it is likely that the actual GPM and head will be the same as the design values. True/False
False
When it comes to the rate of heat loss by conduction and convection, aside from the factor of humidity control, human comfort depends entirely on the WB temperature of the air. True/False
False
When using ratios to calculate the combined temperature of 2 mixed air streams, the sum of the 2 ratios must always be equal to 0. True/False
False
With centrifugal fans, nearly all the air velocity occurs at the side of the outlet nearest to the fan shaft. True/False
False
Psychrometrics is the concepts of start, test, and balance with an emphasis on the documentation of how a mechanical system relates to the other systems of a project. True/False
False Commissioning
Heat that results in a change of state, as from solid to liquid or liquid to vapor, with no change in the temperature of the substance is called sensible heat. True/False
False Latent
Evacuating and charging of a chiller should be done according to the standards published by the EPA. True/False
False Manufacturer
A common unit of pressure obtained when force is measured in pounds and area is measured in square inches, the resulting unit being pounds per square foot (PSF). True/False
False PSI
Testing, balancing, and adjusting are the procedures used to enable the proper shut-down and storage of a mechanical system. True/False
False Start-up
The logical sequence of the start-up and operation of a mechanical system is designated by the abbreviation TAB, which stands for testing, adjusting, and balancing. True/False
False TBA
3units in common use for defining the rate of heat flow are BTU per hour (BTUH), BTU per minute (BTUM), and millions of BTU per hour (MBH). True/False
False Thousands
All outlets or terminal units should be numbered beginning with the unit or outlet ___ from the supply fan.
Farthest
The velocity of air is ___ in the center of a duct.
Fastest
___ dampers are safety devices held in the open position by a fusible link, which will melt when it is subjected to enough heat. A. Splitter B. Fire C. Single-zone D. Manual volume
Fire
The advantage of using a(n) ___ thermometer is that it may be used to read the temperature in a remote location, such as inside a refrigerator with its door closed. A. Infrared B. Liquid-in-glass C. Multi-probe D. Flexible capillary
Flexible capillary
Control valves are used to regulate the ___ through terminal units. A. Pressure of liquid B. Flow of liquid C. Pressure of air D. Airflow
Flow of liquid
During ___, the rate of heat transfer increases with the acceleration in the velocity of the flow of the medium. A. Radiation B. Conduction C. Natural convection D. Forced convection
Forced convection
___ losses occur due to changes in air velocity and to air turbulence. A. Frictional B. Flow C. Static pressure D. Dynamic
Frictional
A(n) ___ should always be directly ahead of a gauge, which will permit removal of the gauge.
Gauge cock
Dial thermometers should be checked against a good ___ thermometer at the beginning of each testing project and periodically thereafter.
Glass stem mercury thermometer
A(n) ___ valve is capable of producing throttling actions and may be used for balancing, although it is not recommended.
Globe valve
The most elementary and accurate pressure measuring device is a ___. A. Thermometer B. Differential pressure gauge C. Gauge manifold D. Manometer
Manometer
For air side balance, all controls should be set to call for ___. A. Minimum heating B. Minimum cooling C. Maximum heating D. Maximum cooling
Maximum cooling
The ___ method for measuring and adjusting air terminals recommends beginning at the terminal farthest from the fan and proceeding toward the fan.
Proportional or Ratio
___ is the study of the physical principals governing the behavior of moist air
Psychrometrics
If air is not cooled to a temperature lower than its initial dew point temperature, then only___ is removed. A. Humidity B. Latent heat C. Moisture D. Sensible heat
Sensible heat
A locked rotor amperage (LRA) rating is typically ___ times the FLA rating of a motor. A. 3 to 5 B. 12 to 15 C. 15 to 18 D. 20 to 25
3 to 5
A fan operating with an inlet pressure of -1.5 in. W.C. total pressure and an outlet static pressure of +2.45 in. W.C. will have a pressure plotted on the fan curve at ___ in. W.C. A. 1.16 B. 2.03 C. 3.95 D. 4.78
3.95
With a perfect vacuum at the pump suction, the maximum lift would be a distance of ___ ft if the liquid is water in a normal temperature range. A. 0 B. 14.7 C. 34 D. 78.6
34
If velocity through a given duct fitting is doubled, the dynamic loss will be increased by ___ times.
4
In a hydronic heating system where water flows at a rate of 5 GPM, enters the boiler at 178° F, and leaves at 200°, the heat transfer from the boiler to the system is ___ BTUH. A. 114 B. 8800 C. 55000 D. 125000
55000
A medium pressure system has velocities greater than 2,000 ft/min or static pressure in the duct up through ___ in.w.g. A. 2 B. 6 C. 10 D. 15
6
For greatest accuracy, the airway in which an anemometer is to be placed should be ___ times the diameter of the instrument. A. 2 to 4 B. 4 to 6 C. 6 to 8 D. 8 to 10
6 to 8
For optimum success when using a velocity impact meter, the system water should be maintained between ___ pH to minimize corrosion. A. 1.4 and 3 B. 5.1 and 6.8 C. 7 and 8.6 D. 10 and 12.3
7 and 8.6
If possible, a traverse should be made at least ___ duct diameters downstream from a distance. A. 1-1/2 B. 3-1/2 C. 7-1/2 D. 10-1/2
7-1/2
Most fume hoods are designed to operate between ___ at the proper sash height. A. 5 ft/min and 10 ft/min B. 25 ft/min and 40 ft/min C. 50 ft/min and 85 ft/min D. 90 ft/min and 110 ft/min
90 ft/min
The latent heat in vaporization of water at standard sea level pressure is ___ BTU/LB.
970
___ is heat that causes changes in the temperature of a substance and can be measured with a thermometer. A. Saturated steam B. Kinetic energy C. Sensible heat D. Latent heat
Sensible heat
The difference between the suction and the discharge reading for a pump will be the ___.
Actual shut-off head
___ means setting automatic controls and the adjustment of any other devices that affect the manner in which a system operates.
Adjusting
Final steps for proportional balancing include ___. A. Adjusting the grille deflections and diffuser cones B. Setting all of the room thermostats for maximum cooling C. Comparing the measured flow in each branch with the design CFM D. Measuring the static pressure at multiple locations
Adjusting the grille deflections and diffuser cones
Current is measured with a(n) ___. A. Ammeter B. Ohmmeter C. Wattmeter D. Voltmeter
Ammeter
To the owner, an adequate job of testing, balancing, and adjusting means ___. A. Broken equipment gets repaired B. The equipment has gone through the period of initial operation without being subjected to improper or damaging operating conditions C. Avoiding complaints and call-backs from clients D. Assurance that what was paid for has been received
Assurance that what was paid for has been received
When both ends of a U-tube manometer are open, the liquid is ___. A. Separated B. Higher in the closed leg C. Higher in the open leg D. At the same height in each leg
At the same height in each leg
A straight, horizontal line on a psychrometric chart indicates that the heat added between 2 points is ___. A. From high-temperature water sprays B. Latent heat only C. Sensible heat only D. Both sensible and latent heat
Sensible heat only
It may be desirable to install ___ to reduce the amount of stratification in a duct.
Baffling
___ is the process used to regulate a distribution system, typically an air handling system and water pumping system,so they deliver the air, water, or other medium to all the intended locations and in quantities intended by design. A. Adjusting B. Balancing C. Start-up D. Testing
Balancing
On a graph, the intersection of an HQ or head-capacity curve with a zero capacity line indicates ___. A. Brake horsepower B. Shut-off head C. Static head D. Water horsepower
Shut-off head
A(n) ___ is an instrument used in the field to determine the DB and WB temperatures and, from them, the relative humidity in an air-conditioned space.
Sling psychrometer
Most air cooling and dehumidifying processes are represented as ___ lines on a psychrometric chart.
Sloping
For a given motor load and speed, an increase in voltage will result in a ___. A. Smaller power factor B. Greater power factor C. Smaller current D. Greater current
Smaller current
Soiling of a ceiling due to smudge can be reduced by installing a(n) ___ around the diffuser. A. Grille B. Outlet C. Control vane D. Smudge ring
Smudge ring
Most pressure leaks can be found audibly, although it may be necessary to use ___ to find some leaks. A. Fabric B. Ammonia C. Soap suds D. Dye
Soap suds
"___" is the term used to define the capacity of a substance to absorb heat as compared to that of water.
Specific heat
Humidity ratio is the weight of water vapor per pound of dry air, also known as ___. A. Latent heat B. Wet-bulb temperature C. Specific humidity D. Saturation temperature
Specific humidity
When testing for psychrometrics problems, equipment selections normally are based on ___ air. A. Standard B. Dry C. Atmospheric D. Moist
Standard
___ air is dry air at 70°F with a pressure of 29.92 in. Hg and a weight of .075 lb/cu ft.
Standard
Upon initial ___ of a system, testing should confirm that the equipment is operating properly and safely.
Start-up
Any reduction in excess ___ will save the fan horsepower, reduce operating cost, and tend to reduce system noise.
Static pressure
Some terminal units have self-contained regulators and require a certain minimum ___ at their inlet for them to work.
Static pressure
___ is a measurement of the resistance a duct system presents to the flow of air.
Static pressure
Fan ___ is equal to the rise in total pressure across the fan, diminished by the velocity pressure created by the fan.
Static pressure.
The 2 types of dial thermometers are ___. A. Stem and flexible capillary B. Steam and gauge C. Rod and flexible capillary D. Rod and gauge
Stem and gauge
A ___ is an electric tachometer that uses an electronically controlled flashing light. A. Centrifugal-type tachometer B. Digital photo tachometer C. Stroboscope D. Chronometric tachometer
Stroboscope
___ head existed when the source of supply is above the center line of a pump.
Suction
When using a U-tube manometer, the pressure is the ___ of the readings in the two legs.
Sum
___ pressure is the actual atmospheric pressure r a specific location and time, and it may be needed for accurate results in some cases when testing air flow. A. Vacuum B. Absolute C. Gauge D. Barometric
Barometric
A(n) ____ tube is a metal tube of flattened oval cross+section and is bent into a part circle.
Bourdon
___ Law states that the volume of gas varies inversely with the absolute pressure when the temperature remains constant. A. The combined gas B. Boyle's C. Charle's D. Gay-Lussac's
Boyle's
___ horsepower is the actual horsepower required to drive a fan. A. Static B. Total C. Start-up D. Brake
Brake
Any significant adjustment of air volume in a distribution system should be done by adjusting branch duct splitters or manual volume dampers, or by ___. A. Introducing a humidifier into the system B. Changing the fan speed C. Changing the direction of the air flow D. Introducing a dehumidifier into the system
Changing the fan speed
When coal is burned under a boiler, its ___ energy is transformed into heat energy in the steam.
Chemical
A ___ combines a revolution counter and a stop watch in one instrument. A. Chronometric tachometer B. Stroboscope C. Digital photo tachometer D. Centrifugal-type tachometer
Chronometric tachometer
___ is a well-planned process of verifying and documenting that a project or system can perform as the design intended.
Commisioning
A(n) ___ gauge should be used where exposed to vacuum.
Compound
___ is the transfer of heat by movement of a fluid, such as air or water.
Convection
Before any system can be balanced properly, the ___ must develop enough static pressure for the system, and the air volume handled by it must be adequate for the system. A. Air damper B. Supply fan C. Filter D. Return air fan
Supply fan
The resistance to air flow in a straight, unobstructed duct is caused primarily by ___. A. A low velocity of the air B. A difference in pressure from either end of the duct C. Static pressure D. Surface friction as the air scrubs the duct walls
Surface friction as the air scrubs the duct walls
Inlet ___ pressure is equal to inlet static pressure plus inlet velocity pressure. A. Filter B. Total C. Exhaust D. Box
Total
___ pressure is the sum of static pressure and velocity pressure. A. Discharge B. Air flow C. Total D. Impact
Total
Pumps are rated in volume of fluid pumped, usually in GPM, against a certain pressure of head, called ___.
Total dynamic head
2 forms of convection are natural and forced convection. True/False
True
A 10° temperature rise is different than a temperature of 10° True/False
True
A U-tube manometer could be made from a piece of glass or a clear plastic tubing, a ruler, and some water. True/False
True
A U-tube manometer is inherently 100% accurate. True/False
True
A chronometric tachometer is accurate within .05% True/False
True
A duct system is classified as high pressure when duct velocity is greater than 2,000 ft/min or static pressures in the duct are more than 6 in.w.g. And up to 10 in.w.g. True/False
True
A pump does not suck water into its inlet connection. Instead, atmospheric pressure pushes the liquid up into the pump. True/False
True
A sling psychrometer must be whirled around to produce an air velocity of at least 700 ft/min relative to the thermometer bulbs. True/False
True
A small motor operating with no load will have a very low power factor. True/False
True
A stream discharged adjacent to a ceiling will tend to follow along in contact with the ceiling until its velocity is greatly diminished. True/False
True
A system can be placed in operation after gathering information and documentation on the testing results and inspecting that the installation appears safe to start. True/False
True
A system that requires a chilled water supply of 45°F will not ordinarily be satisfied by the water supply at 50°F, even though the total BTUH rate may be as required. True/False
True
A tachometer must be held so the instrument spindle is in line with the shaft whose speed is being measured. True/False
True
A thermometer well should extend at least halfway across a pipe. True/False
True
A turbine thermometer provides an output signal that varies with the flow rate. True/False
True
A/C equipment can treat moist air by adding or removing sensible heat, adding or removing moisture, or by a combination of changes in both sensible heat and latent heat. True/False
True
Adiabatic saturation is the process of saturating air with moisture without any change in the total heat. True/False
True
An inch of water is a unit used to measure the resistance exerted by a vertical column of water one inch in height. True/False
True
Anemometers measure air velocity directly. True/False
True
Balancing procedures ensure that media, such as air and water, are available at the correct locations and in quantities needed. True/False
True
Before each use, thermometers should be visibly checked for liquid separation. True/False
True
Changes in DB temperature are indicative of changes in sensible heat True/False
True
Every fan operates only along its performance curve. True/False
True
Fans used in heating, ventilating, and A/C work are divided into two general classifications, centrifugal fans and axial flow fans. True/False
True
For reasons of economy or available building space, direct return riser systems may be preferable to reverse returns for each individual building. True/False
True
Gauge pressure, when measured in pounds per square inch, is indicated by the abbreviation PSIG. True/False
True
If a fan serves only one hood and is not at a great distance from the hood, it may be assumed that the airflow measured at or near the fan is equal to the air volume entering the hood. True/False
True
If a thermometer must be removed from a refrigerator, coil housing, etc., to be read, it will cease to be in contact with the air and thus will not give a true reading. True/False
True
If a velocity pressure has been measured, the corresponding velocity can be determined. True/False
True
If moist air is cooled to a temperature below its initial dew point, a portion of the moisture in the air will condense and be separated from the air. True/False
True
If the variation in the face velocity of a grille exceeds 25%, the air flow should be balanced to obtain a more even distribution over the face of the grille. True/False
True
In A/C systems, the design of duct and fan systems is based on volume (in CFM). True/False
True
Individual outlet or inlet volume control dampers and register dampers should not be used for balancing other than to balance flow between individual outlets on a duct run or for touch-up adjustment to local occupant comfort. True/False
True
It is generally agreed that air-handling systems should be tested and balanced before work is done on hydronic, steam, or refrigeration systems. True/False
True
Liquid-in-glass thermometers have the advantage of being inexpensive, easy to carry, and reasonably accurate. True/False
True
Many terminal units or control boxes use a device called a constant volume regulator, the purpose of which is to maintain a constant flow of air in the system regardless of the pressure in the supply duct. True/False
True
No single specific balancing procedure applies to all systems. True/False
True
One way to measure the current flowing through a conductor is to break the conductor and insert a meter in the circuit. True/False
True
Proper hydronic system start-up should minimize the amount of make-up water needed. True/False
True
Schematic layouts should indicate all dampers, regulating devices, terminal units, outlets, and inlets of a system. True/False
True
Sheaves with belt speeds above 6,000 FPM to 6,500 FPM require special balancing. True/False
True
Since cooling capacity usually is more critical than heating capacity, balancing is normally done with dampers set for full cooling. True/False
True
Splinter dampers are used to direct air from a main supply duct into a branch duct. True/False
True
Static pressure is pressure within a duct that tends to burst the duct. True/False
True
Static pressure readings, when referred to fan capacity data, may give incorrect results. True/False
True
The Pitot tube, when used with an appropriate pressure gauge, is the preferred device for measuring the air velocities in a duct. True/False
True
The balancing and adjustment of a system may require adjustment of the blade pitch. True/False
True
The efficiency of a motor determines the power consumed by the motor as compared to the horsepower produced. True/False
True
The final balancing of an air system includes calibrating the operating and safety controls. True/False
True
The rate of flow is directly proportional to the change in temperature and to the area of the surface through which heat will flow. True/False
True
The type of pressure gauge to be used depends on the magnitude of the velocity pressure being measured and the accuracy desired. True/False
True
There are 3 important factors concerning the behavior of gases: their temperature, the pressure being exerted on them, and their volume. True/False
True
Thermometer test wells are used to house thermometer bulbs at locations where the temperature of fluid in a pipe is to be measured. True/False
True
Three-phase motors can be reversed by interchanging any two of the three power leads to the motor. True/False
True
Velocity head in a pump is usually insignificant and can be neglected. True/False
True
Velocity pressure is not read directly but as the difference between total pressure and static pressure. True/False
True
Water horsepower is the theoretical horsepower that would be required is a pump were 100% efficient. True/False
True
When a conversion is performed from Hg. to feet of system fluid, the correct conversion will depend on the density of the fluid. True/False
True
When it is necessary to change one belt in a multi-belt drive, all belts in the drive should be replaced with a matched set. True/False
True
When preparing the start-up process for a hydronic system, outdoor conditions usually determine which hydronic system is started first. True/False
True
When using a Bourdon gauge, normal calibration consists of subjecting the gauge to a known pressure, as applied by a "dead-weight" tester, and resetting the linkage or the pointer to read correctly. True/False
True
When using a digital photo tachometer, the rotating object is marked with a reflecting tape, and the probe is then held 1/4" to 25' from the rotating object. True/False
True
The intensity of heat is usually measured using the Fahrenheit temperature scale in the U.S. True/False
True Because 'Murica
The conversion of the upstream static pressure to the velocity pressure of an orifice is not completely efficient, but there is a loss due to ___.
Turbulence.
The actual balancing procedure of air distribution to be used will depend on the ___. A. Size of the system B. Location of the system C. Type of system D. Capacity of the system
Type of system
___ manometers are most suitable for measuring pressures of several in.w.g. or more.
U-tube
The freezing point of mercury is ___°F.
-40
Absolute zero is equal to ___. A. -57°F or -49°C B. -128° F of -89°C C. -275° F or -171°C D. -460°F or -273°C
-460°F or -273°C
The coefficient of performance is normally in the range of ___. A. .2 to .3 B. .6 to .7 C. 1.0 to 1.1 D. 1.4 to 1.5
.6 to .7
Small- to medium-size equipment usually is supplied with an adjustable pitch motor sheave, which permits adjusting the speed within a range of perhaps ___ without changing sheaves. A. 0.5% tp 1% B. 5% to 10% C. 25% to 30% D. 45% to 50%
25% to 30%
Head is equal to ___ if the pump discharge gauge reads 128 psi and the suction gauge reads 20 psi. A. 64 in.Hg. B. 148 psi C. 250 ft D. 296 ft.w.g.
250 ft
Oil having a specific gravity of about 0.83, as compared to water, will rise a distance of about ___ in. at a pressure of 1in. of water. A. 0.21 B. 0.83 C. 1.2 D. 1.83
1.2
The tension on a belt is about right if it can be depressed about ___ under normal pressure from the thumb. A. 1/4" to 1/3" B. 1/2" to 3/4" C. 1" to 1-1/3" D. 1-1/2" to 2"
1/2" to 3/4"
If a gauge is of a large diameter, such as 8", differential pressures can be read accurately to the order of ___ ft. w.g. A. 1/4 B. 1/2 C. 2/3 D. 1
1/4
After all tests and adjustments of fan speed have been made, if the measured CFM of the supply fan, return air fan, or central exhaust fan varies by more than ___% from the design, the drives of each fan must be adjusted to obtain approximately the required air quantities. A. 10 B. 20 C. 30 D. 40
10
It is normally considered that there is an adequate and practical balance when the air quantities, as measured on the job, are within plus or minus ___% of design volumes. A. 10 B. 15 C. 20 D. 25
10
When performing an initial fan check, voltage should be within plus or minus ___% of the motor nameplate rating, and 3-phase voltages must not vary from one another beyond acceptable limits. A. 3 B. 5 C. 10 D. 15
10
A condenser water system should be designed to produce enough capacity after about ___ years of accumulation of corrosion and scale.
10 years
For traversing square or rectangular duct, the cross-section should be divided into at least ___ equal square areas.
16
___ is a measure of the actual weight of water vapor per unit volume of air.
Absolute humidity
___ pressure is the sum of atmospheric pressure plus gauge pressure. A. Vacuum B. Absolute C. Barometric D. Atmospheric
Absolute
A practical measure of heat is the ___. A. BTU B. Melting point C. Boiling point D. PSIG
BTU
___ remains constant in a duct system regardless of changes in air density, provided the fan operates at constant speed and the duct system remains unchanged.
CFM
Pump ___ is expressed as the flow rate or volume, usually in GPM, that a pump can discharge against a given pressure or head.
Capacity
____ is a result of insufficient available net positive suction head that cause low pressures, such that some of the pumped liquid flashes into vapor and forms bubbles. A. Cavitation B. Static head C. Friction head loss D. Dynamic loss
Cavitation
Because open systems are highly susceptible to ___ with the passing of time, pipe friction values should be greater than those for new pipe. A. Leakage and pipe breaks B. Corrosion and roughening of the pipe C. Buildup on pipe walls D. Fitting expansion
Corrosion and roughening of the pipe
A ___ arrangement is when one of the heat transfer media travels in a path that is at right angles to the path of the other medium. A. Cross-flow B. Counterflow C. Parallel D. T-flow
Cross-flow
On a psychrometric chart, specific volume is measured in ___. A. Pounds per square inch B. Cubic feet per pound C. BTU per pound D. Cubic feet per minute
Cubic feet per pound
A clamp-on ammeter can be clamped around a conductor to measure the ___ through the conductor. A. Voltage B. Current flow C. Capacitance D. Resistance
Current flow
Glass-stem test thermometers of good quality have the temperature scale painter on the stem. True/False
False
If a thermometer well cannot be installed exactly vertical, then it must be installed so the open end is not more than 90° across the pipe. True/False
False
___ control air volume in duct systems by imposing a high static pressure loss as airflow is restricted.
Dampers
During the application of sprays, if the spray water is colder than the dew point of the entering air, the sprays will ___ the air.
Dehumidify
If balancing has been done with a dry cooling coil, the total air flow must be rechecked when the coil is ___ and is therefore wet, as its resistance to air flow will be greater when wet than when dry.
Dehumidifying
The usual purpose of measuring the velocity of air in various parts of an air handling system is to ___. A. Compare temperatures of the air through various parts of the system. B. Determine the volume of the air flowing. C. Direct the desired amount of air to a specific area D. Find where air is being dropped or diverted from the system
Determine the volume of the air flowing
___ is the DB temperature at which the atmospheric air becomes saturated with water vapor. A. Dew point temperature B. Enthalpy C. Humidification D. Sensible heat
Dew point temperature
___ are more rugged and easier to read than glass-stem thermometers, and they are fairly inexpensive.
Dial thermometers
According to the best recommendations, when using a sling psychrometer ___ water should be used to wet the wick, using a medicine dropper to transfer the water from the bottle to the wick.
Distilled
Where banks of filters or coils are large enough to make them accessible, measurements should be made on the ___ side of the filter or coil.
Downstream
A(n) ___ is any localized feeling of coolness or warmth (but generally associated with coolness) due to temperature and rate of movement of a current of air.
Draft
___ air is atmospheric air from which all water vapor, and also all contaminants, such as smoke, etc., have been removed.
Dry
A(n) ___ is performed by sealing off the system or section of a system to be tested, applying pressure with a blower, and measuring the volume of air supplied by the blower.
Duct leakage test
If the pressure inside a duct is greater than the pressure outside the duct, then air will flow into the duct. True/False
False
In a round duct, velocity pressure readings should be taken at the edge of the duct. True/False
False
Hand-held chronometric tachometers with speed ranges contain a centrifugal lay operated mechanism similar to the fly-ball governor on a stationary stem engine or the governor on a gasoline engine. True/False
False
The sum of the areas of all the vena contractas existing at a grille or diffuser is called the ___ area of the grille or diffuser. A. Drop B. Gap C. Operating D. Effective
Effective
Heat is a form of ___.
Energy
____ is the capacity for doing work.
Energy
___ is a measure of the total heat energy of air.
Enthalpy
Friction losses for fittings usually are given in ____. A. Inches of suction lift B. Feet of pressure drop C. Inches of suction head D. Equivalent feet of pipe
Equivalent feet of pipe
The flow of heat from one object or substance to another is referred to as heat ___. A. Loss B. Exchange C. Flow D. Balance
Exchange
The term "___" is particularly applicable to the average velocity of the air entering an intake grille.
Face velocity
A kilowatt (kW) is a unit of power equal to 100 watts. True/False
False
A method of uniting a separated liquid column in a thermometer is to cool the bulb enough to draw all of the liquid out of the bulb. True/False
False
A voltage imbalance of 10% on a motor is considered the maximum by industry standards. True/False
False
Any shortage of the air in a hydronic system results in a corresponding increase in capacity. True/False
False
As a load increases, the power factor is reduced. True/False
False
Balancing may include items such as adjusting grille and diffuser air patterns to eliminate drafts or changing the air volumes to produce more desirable temperatures in some areas. True/False
False
Dial thermometers have a relatively shot time lag. True/False
False
During the operation of a gauge modification using a single standard gauge, the gauge glass is fully tightened into place to prevent damage. True/False
False
Electrical testing instruments with wireless communications contain a very sensitive meter, usually a milliammeter, which can measure current in hundredths of an ampere. True/False
False
Fans are rated on the basis of the amount of velocity pressure they can develop as an indication of the amount of duct resistance they can overcome. True/False
False
Flow hoods are made of aluminum. True/False
False
For testing and balancing purposes, the dynamic loss in a square elbow with properly made turning vanes will be roughly equal to the friction in a duct that is 10 duct diameters in length. True/False
False
A good rule of thumb is, for every 35° increase above 85°, the belt life is reduced by ___.
Half
Input voltage and current measurements on variable frequency drives usually will be affected by ___.
Harmonics
A turbine flow meter determines the fluid flow rate to a(n) ___.
Heat exchanger
A pyrometer is used to measure ___ A. Low temperatures B. High temperatures C. Low pressures D. High pressures
High temperatures
Belts are rated by ___ per belt.
Horsepower
The approximation or estimation of ___ is a valuable indication of the flow or the component or system performance.
Horsepower
The pressure exerted by a liquid due to its own weight is called ___ pressure.
Hydrostatic pressure
Class ___ construction is standard, relatively lightweight fan construction A. I B. II C. III D. IV
I
The larger the area of a duct, the ___ the velocity of the air.
Lower
A(n) ___ is an open tube face directly into an air stream to receive the effects of both static pressure and velocity.
Impact tube
A(n) ___ manometer is a variation of a well-type manometer in which the indicating leg or tube is placed in a sloping position rather than vertically. A. Inclined B. Handheld C. Dry-type D. U-tube
Inclined
The ___ is best suited to measuring fairly low pressures, such as in the range of 0.10 to 1.0 in.w.g. A. Inclined-vertical B. Well-type manometer C. Inclined draft gauge D. Dry-type draft gauge
Inclined draft gauge
___ are used for a non-contact temperature measurement. A. Thermistors B. Pyrometer C. Infrared thermometers D. Flexible capillary thermometers
Infrared thermometers
One factor involved in the measurement of heat is the ___ of heat as indicated by the temperature of the substance. A. Quantity B. Intensity C. Quality D. Weight
Intensity
Initial start-up and balancing usually occurs when a building ___. A. Is empty or only partially occupied B. Has been occupied for one week C. Has been occupied for one month D. Has been occupied for one year
Is empty or only partially occupied
As a chilled water flow rate decreases in a hydronic terminal unit, the coil surface temperature rises, and ___ heat capacity is lost. A. Total B. Specific C. Sensible D. Latent
Latent
Total heat is equal to sensible heat plus ___ heat.
Latent
Operation of a(n) ___ thermometer is based on the principle that materials expand when heated and contract when cooled.
Liquid-in-glass
A duct system is classified as a ___ system when velocity are less than 2,000 ft/min and static pressure in the duct is 2 in.w.g. or less. A. Stagnant flow B. Resistive C. Low pressure D. High pressure
Low pressure
When a Bourdon gauge is used, pressure ranges should be selected so the pressures to be measured fall in the___ of the scale range. A. First half B. Middle two-thirds C. Last third D. Second half
Middle two-thirds
The curved upper surface of a liquid column in a manometer is called the ___.
Miniscus
A common process occurring in A/C systems is the mixing of 2 streams of ___ air.
Moist
Brake horsepower may be estimated by comparing the ___ voltage and current with the actual voltage and current as measured on the job.
Motor nameplate
___ can be arranged for either parallel operation or opposed blade operation.
Multi blade danpers
When balancing ___, check the fan CFM against the cooling coil CFM.
Multi-zone units
The ___ divides pulleys into three standard series: light duty, medium duty, and heavy duty. A. American Society of Heating, Refrigeration, and Air-Conditioning Engineers, Incorporated (ASHRAE) B. Airflow Dynamics Corporation of America C. National Belting Committee (NBC) D. National Industrial Belting Association (NIBA)
National Industrial Belting Association (NIBA)
___ may be considered to be the amount of pressure, in excess of the vapor pressure, required to overcome internal pump losses.
Net positive suction head available
If a bypass or hot-deck damper in an A/C system does not close properly when a need for maximum cooling is required, the supply air will___ may have been intended. A. Be colder than it B. Not be as cold as C. Not circulate as D. Be more humid than
Not be as cold as
The unit of impedance in alternating current circuits is measured in ___.
Ohm
The relationships among voltage, current, and resistance or impedance are given by ___.
Ohm's law
A(n) ___ can be used to check for an open circuit, or circuit continuity.
Ohmmeter
The ___ of a system is the condition of CFM and static pressure at which the system actually operates.
Operating point
A(n) ___ is any opening in the wall of a containing vessel.
Orifice
___ is the theoretical velocity of air as it leaves a fan outlet.
Outlet velocity
A manometer may be equipped with ___, which can seal the mercury within the manometer in the event there is sufficient pressure to raise the mercury up out of the manometer.
Over pressure trap
___ is the pressure in pounds that a fluid is exerting on a surface one square inch in area.
PSI
___ is a change in a measurement reading due to a change in the position of the eye.
Parallax
It is common to find ___ pumps on hydronic loops. A. Standby B. Series configured C. Swing D. Parallel configured
Parallel configured
Maximum suction lift would be theoretically possible if there was a(n) ___ at the pump suction.
Perfect vacuum
The first step in starting a chiller is to ___. A. Flush the chiller with bleach B. Flush the chiller with water C. Place the condenser water system in operation D. Check the cooling fan
Place the condenser water system in operation
Belt tension testers operate on the principle of measuring the force in ___ needed to depress or deflect the belt a given amount.
Pounds
A(n) ___ is simply the ratio of true power and apparent power.
Power factor
The bending of a spring in a dry-type draft gauge is proportional to the ___ to be measured.
Pressure
Flow rates usually are determined by measuring the ___ across a piece of equipment or a balancing device, and then referring to the performance or calibration data to determine the flow rate.
Pressure drop
The ___ in a duct are classified as static, velocity, and total.
Pressures
The ___ fan characteristically has a wheel that is narrow but of a comparatively large diameter.
Radial bladed
___ is a means of energy transfer similar to that produced by light waves and radio waves.
Radiation
Adjustment of the airflow normally would be done by ___ until obtaining a pressure drop reading that corresponds to the desired CFM. A. Resetting a damper in the box B. Inserting a rubber stopper into the Pitot tube C. Replacing the regulator D. Placing a hood over the diffuser
Resetting a damper in the box
System ___ is the sum total of all pressure losses through the ductwork and through filters, coils, dampers, etc. A. Drop B. Resistance C. Flow D. Draw
Resistance
Electrical energy can be converted to heat energy by passing the electricity through a(n) ___.
Resistance heating coil
Whenever there are 2 or more terminal units on a 2-pipe system, the return may be arranged in one or two commonly used ways, the direct return or the ___ return. A. Reverse B. Diverting C. Inverse D. Indirect
Reverse
A(n) ___ consisted of a light windmill or propeller wheel that is connected through a gear train to a set of dials that read the linear feet of air passing through the wheel.
Rotating vane anemometer.
When air holds the maximum amount of water vapor possible at a given temperature and pressure, the air is said to be ___. A. Wet B. Dry C. Unsaturated D. Saturated
Saturated
A(n) ___ is an instrument used to measure the speed at which a shaft or wheel is turning.
Tachometer
For new belt drives, the ___ must be rechecked after initial operating periods, such as after the first 12 hrs and 72 hrs of operation, and adjusted if necessary.
Tension
A(n) ___ is a device or unit, often a box, located where a supply duct or duct branch terminates and the air is introduced into the space to be conditioned.
Terminal unit
___ can provide assurance that equipment can operate safely and without danger of being damaged because of being overloaded.
Testing
Fluid temperature may be roughly determined with a strap-on thermometer strapped to a pipe or by putting___. A. The bulb of a thermometer in contact with a pipe and covering it with putty B. A thermometer bulb directly into the branch main C. The shut-off valve in a wide open position and reading the temperature at the opening D. A strap-on thermometer around the generator
The bulb of a thermometer in contact with a pipe covering it with putty
A multi-purpose pump discharge valve acts as a check valve to prevent ___ when the pump is off and to prevent stray flows between operating and non-operating piping circuits. A. The gravity circulation of hot water B. The forced circulation of coolant C. Improper pump operation D. An increase of internal temperature
The gravity circulation of hot water
Written records of ___ will provide a reference point and a basis for changing a system to meet new conditions.
The initial operation
A(n) ___ is a type of transistor or semiconductor and is a solid-state electronic device.
Thermistor
___ is the distance from a grille or the radius from a ceiling diffuser to a point where motion of the mixed air stream is reduced to a given velocity, called the terminal velocity. A. Throw B. Spread C. Drop D. Outlet
Throw
___ is the velocity at the outermost part of a fan blade relative to the fan housing. A. Tip speed B. Dynamic loss C. Fan performance D. Horsepower
Tip speed
A pump suction pressure less than atmospheric would be read as a(n) ____ in inches of mercury.
Vacuum
The total dynamic head of a pump consisted of ___. A. Velocity head, atmospheric pressure, and dynamic losses B. Static head, atmospheric pressure, and leakage losses C. Velocity head, friction losses, and static head D. Friction losses, dynamic losses, and static head
Velocity head, friction losses, and static head
The coefficient of performance is a number that considers effects of the ___.
Vena contractas
A(n) ____ operates on the same general principle as an orifice, but it is shaped so as to avoid abrupt changes in velocity.
Venturi
Voltage, or electrical potential or pressure difference, is measured in ___ . A. Amperes B. Watts C. Ohms D. Volts
Volts
An air ___ is a chamber containing a system of water sprays through which air is passed. A. Humidifier B. Chiller C. Dehumidifier D. Washer
Washer
When a manometer is used on a hydronic system, ____ from the system will rest on top of the mercury in the manometer. A. Coolant B. Air C. Water D. Lubricating oil
Water
___ in a thermometer well may be undesirable if the test well is made of a type of steel that could rust. A. Lubricating oil B. Air C. Mercury D. Water
Water
Power is measured with a(n) ___.
Wattmeter
One leg of a(n) ___ manometer is a tube but the other leg is an enlarged reservoir or well. A. Flexible tube B. Well-type C. U-tube D. Inclined-vertical
Well-type
___ is the temperature registered by a thermometer whose bulb is covered by a wick that is wetted with water and exposed to a current of rapidly moving air.
Wet bulb temperature
If the maximum RPM of a centrifugal fan is exceeded, the shaft may ___.
Whip
For maximum heating or for maximum cooling with refrigeration, the return air damper should be, ___, and the outside air damper set for minimum outside air. A. Partially open, the relief damper shut B. Wide open, the relief damper partially open C. Partially open, the relief damper fully open D. Wide open, the relief damper shut
Wide open, the relief damper shut