Set B Volume 4

Front 1

In air distribution systems, the three basic categories of fans are

Back 1

centrifugal, special design , and axial

Front 2

What are the width and inlet constructions of centrifugal fans?

Back 2

SWSI and DWDI

Front 3

The purpose of vanes of a vaneaxial fan is to

Back 3

straighten out the airs spiraling motion

Front 4

A fan drive is an assembly made up of

Back 4

a motor sheave, fan sheave, and connecting belts

Front 5

To prevent needless problems to your HVAC equipment, which item should you check during V-belt inspection?

Back 5

Proper alignment

Front 6

The most common size v-belts used in HVAC systems are

Back 6

A through D

Front 7

What is generally the proper tension for the top side of fan belts?

Back 7

1/2 to 1 inch deflection

Front 8

A single-duct system become a low-press reheat system when

Back 8

heating coils are inserted into the duct system downstream of the cooling coils

Front 9

The individual zone or space control is provided in an induction system by

Back 9

heating the secondary air

Front 10

which multiple-path system uses a mixing valve to control zone temp by mixing warm and cold air in proper rotation

Back 10

dual-duct

Front 11

what is one way to reduce energy cost of a dual-duct system with no cooling load?

Back 11

operate the system as a single zone

Front 12

which multiple-path system meets the requirements of the different zones by mixing cold and warm air through zone dampers at the central heat, ventilation, and HVAC unit?

Back 12

multizone

Front 13

The supply pressure loss data for equipment used in piping systems normally come from

Back 13

manufacturers

Front 14

what is static head?

Back 14

pressure due to the weight of the fluid above the point of measurement

Front 15

how many intakes does the single-suction pump impeller have

Back 15

one

Front 16

which type pump casing collects water from the impeller and discharges it parallel to the pump shaft?

Back 16

Diffuser

Front 17

some leakage at the packing gland of a pump is needed to

Back 17

lubricate and cool the area between the material and shaft

Front 18

pumps with mechanical seals

Back 18

must be run dry

Front 19

Destructive pitting and wearing of a pump impeller and casing as well as noise and vibration can be caused by

Back 19

cavitation

Front 20

What is normally the cause of vortex in a piping system

Back 20

configuration of the piping system

Front 21

what do manufacturers use to show how pumps respond under different operating conditions

Back 21

A performance curves graph

Front 22

After each major repair to a pump or when there is an indication that the system flow is not correct, what do you check?

Back 22

pump performance

Front 23

what is the maximum allowable working pressure for low-pressure heating boilers with a maximum temperature limitation of 250 degreesF

Back 23

160 PSI

Front 24

what is the usual pressure for medium-pressure heating boilers when the usual design supply temperature is approximately 250 to 350 degF

Back 24

150 PSI

Front 25

what is the maximum allowable working pressure for high-pressure heating boilers with a max temp limit of 450 degF

Back 25

300PSI

Front 26

What would be the acceptable temp and pressure of a chilled-water supply system

Back 26

48 degF and less than 125PSI

Front 27

which piping system is a continuous run of pipe or tbe from the boiler or chilled water supply connection back to the boiler or chiller?

Back 27

series-loop

Front 28

which hydronic distribution system uses a special diverting tee that creates a pressure drop in the main flow to divert a proportion of the main flow to the terminal unit.

Back 28

one-pipe

Front 29

since water flow distance from and to the boiler is virtually the same through any unit, balancing valves require less adjusting on the

Back 29

two-pipe reverse return

Front 30

which hydronic distribution system uses a special three-way valve at the inlet to the coil to admit water from either the hot-or cold water supply in sequence as required.

Back 30

three-pipe

Front 31

when a terminal unit of hydronic distibution system is provided with two independent water coild, one served by hot water, the other by cold water, this is an example of a

Back 31

four-pipe system.

Front 32

If air and other gases are not removed from the hydronic piping flow circuit, they may cause

Back 32

air binding

Front 33

all low points on hyrdronic systems should be equipped with

Back 33

drains

Front 34

when the condensate of a steam system has cooled below the condensing temp this is referred to as

Back 34

subcooling

Front 35

Because it is necessary to keep a steam system in service at all times, what is installed around the auto temp control valve?

Back 35

A bypass

Front 36

Which steam trap reacts to a difference in the temperature between the steam and condensate?

Back 36

thermostatic

Front 37

which thermostatic trap is not adversely affected by super heated steam?

Back 37

Bimetallic

Front 38

when pressure-reducing valves are used in a steam system, what must also be used?

Back 38

Relief devices

Front 39

In hydronic heating and cooling units, radiators are rated in terms of the square feet of

Back 39

equivalent direct radiation

Front 40

The square feet of equivalent direct radiation of a radiator depends upon radiator

Back 40

capacity and configuration

Front 41

The primary types of baseboard units are

Back 41

radiant, radiant-convector, and finned-tube

Front 42

Hot-water panel heaters include the

Back 42

ceiling, wall, and floor panel types

Front 43

when lubricating unit ventilator fan and motor bearings, you should

Back 43

follow the manufacturers recommendations

Front 44

which duct system terminal unit is supplied with both hot and cold air?

Back 44

dual-duct

Front 45

Because the pressure in the hot and cold ducts of a dual-duct terminal may vary over a wide pressure range due to the demand for the hot and cold air varying throughout the building, it is important to have

Back 45

an auto airflow control device

Front 46

which duct system terminal unit has a manually operated damper that is adjusted when the system is initially balanced and then left in that position to maintain constant airflow?

Back 46

single-duct

Front 47

how does the induction unit circulate air from the room through the coil?

Back 47

it induces air through the coil

Front 48

normally, the basic central station heating, ventilation, and air conditioning equipment in the air/hydroponic unit is located

Back 48

outside the conditioned are

Front 49

In a central station unit, heat recovery equipment may be placed between the outdoor intake and coils, and in mild climates, may replace the

Back 49

preheat coil

Front 50

The use of a return-air fan in a central station unit is optional but generally is essential for proper operation of

Back 50

larger systems

Front 51

when the ventilation by exhaust method provides ventilation for fan-coil units, the entire building

Back 51

is placed in a negative pressure

Front 52

which combination air/ hydronic unit uses air from a central air-conditioning unit that furnishes the ventilation, required dehumidification, and motive power for including the secondary air?

Back 52

induction

Front 53

what is the most important part of a valve

Back 53

throttling nut

Front 54

what is the most common type of two-position valve used in control applications?

Back 54

single-seat

Front 55

which item is a three way valve that has one input and two outputs?

Back 55

diverting

Front 56

what type of valve normally controls steam-to-water or steam-to-air heat exchangers?

Back 56

two-way

Front 57

which multi-blade dampers use a linkeage that causes the adjacent blades to move in opposite directions?

Back 57

opposed

Front 58

which option best describes a damper flow characteristic?

Back 58

relationship between the position of the damper and the percent of air that flows through it

Front 59

face and bypass control of a heating or coolign coil is done by

Back 59

modulating the volume of air through the coil

Front 60

In what two ways are coils basically constructed?

Back 60

Bare tube or pipe and extended surfaces

Front 61

For a heating steam coil to operate properly, eliminate

Back 61

all noncondensables

Front 62

Before you clean an HVAC coil, what should you do to the ducts in and out of the coil?

Back 62

Isolare them

Front 63

With which residential humidifier does the humidification rate var with the temp, humidity, and velocity of the air?

Back 63

pan type

Front 64

which humidification method is essentially an isothermal process

Back 64

steam type

Front 65

manometers are used with filters to measure the

Back 65

pressure drop across the filter

Front 66

which filter is recommended to remove very fine dust particles from the air?

Back 66

Electronic air cleaner

Front 67

The basic types of supply-air outlets are

Back 67

grilles, slot diffusers, ceiling diffusers, and air-distributing ceilings.

Front 68

For what type of installations are the perpendicular-flow slot diffusers best suited?

Back 68

High sidewall and perimeter

Front 69

which type of heat recovery equipment turns between 2 and 8 revolutions per minute?

Back 69

Heat wheel

Front 70

what type of heat recovery device operates in a manner similar to a heat pipe except for the working fluid?

Back 70

coil loops

Front 71

The output capacity of a heat pump is strongly dependent on the

Back 71

available source of heat

Front 72

What type of heat exchanger is designed for pump flow of water from the boiler through the shell?

Back 72

Water

Front 73

Air in HVAC work is considered and treated as

Back 73

an individual gas

Front 74

What is the formula for calculating the volume of airflow through a duct

Back 74

cfm= area x velocity

Front 75

Which term is a measurment of resistance to the movement of air that is being forced through an HVAC system?

Back 75

Static pressure

Front 76

A velocity-to -static-pressure conversion generally occurs in the

Back 76

transition duct at the discharge of a fan

Front 77

As air flows from the discharge or intake of a fan to the ends of the duct runs, the gauge pressure

Back 77

decreases to zero

Front 78

The system resistance curve is a plot of the

Back 78

pressure required to move air through the system

Front 79

After you level and zero the quarter-inch inclined manometer, connect its hoses to the

Back 79

pilot tube

Front 80

When you attachthe pitot tube to the combination incline and vertical manometer, connect the hose from the left side to the

Back 80

total pressure leg of the pitot tube

Front 81

how is the pitot tube inserted into duct work?

Back 81

parallel to and facing the airflow

Front 82

what is the first step of the general procedure for testing and balancing systems?

Back 82

preparing test reports

Front 83

Under what step of preparing test reports does listing systems in groups, supplies, returns and exhausts come?

Back 83

Filling out an air system recap sheet

Front 84

the last step in fillinf out the fan test report is filling in the

Back 84

static pressure drops box

Front 85

upon taking startup readings during equipment check out, one thing you should listen for is

Back 85

bursting or collapsing ducts

Front 86

Before you balance outlets, what should you check to make sure of the correct amount of airflow?

Back 86

total airflow

Front 87

what is the first step in proportionate balancing?

Back 87

spot-check the end outlets closest to the fan

Front 88

when using the proportionate balancing method, the last step in balancing a low-pressure single zone system is to

Back 88

go back to the fan

Front 89

When you recheck equipment readings what should you do if the total outlet cubit feet per minute is 10 percent or more under or over the design cfm?

Back 89

increase or decrease the fan revolutions per minute

Front 90

In which method of indoor air quality control must you consider the increasing heat load

Back 90

ventilation

Front 91

the orifice-plate flowmeter must be installed with

Back 91

a straight length of pipe upstream and downstream of the plate

Front 92

Which hydronic flowmeter is a variable-orifice flowmeter that combines a flowmeter and balance valve in one unit?

Back 92

Circuit tester

Front 93

"List the valves and terminals in the order the occur" falls under which step of preparing water-balance test reports?

Back 93

fill out the flow or pressure-drop water-balance report

Front 94

"list the coil identification room number in sequence" falls under which step of preparing water-balance test reports

Back 94

Fill out the temp water-balance report

Front 95

What is the first step for taking startup reading s during chilled-and hot water system balancing?

Back 95

read the pump static pressure with the pump off

Front 96

what is one step in balancing water terminals

Back 96

read and record initial flows without making adjustments

Front 97

Exposing an original and a translucent tracing paper to a strong light produces a copy with white lines on a blue background that is called

Back 97

a blueprint

Front 98

the reason an object on a blueprint is scaled to a smaller size is that it can

Back 98

be placed on smaller sheets without crowding the views

Front 99

when a building is divided into subsystems during an energy audit, which subsystems included the plumbing, HVAc and control systems?

Back 99

energized subsystem