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UA Star Exam > Hydronics > Flashcards

Hydronics Flashcards

1
Q

what is the definition of human comfort relative to temperature

A

When you feel neither warm nor cool

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2
Q

Which type of hydronic system would use gravity flow

A

High temperature heating

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3
Q

Describe hydronic system

A

Heating and cooling system that uses water or or HTF as a heat transfer medium

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4
Q

brine or a water glycol mixture is commonly referred to as

A

HTF

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5
Q

How Many BTU’s are required to heat one pound of water from 32 to 212

A

180 BTU 212-32

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6
Q

In order to provide accurate indoor temperatures the heat supply to the building must be equal to

A

The heat loss of the building

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7
Q

What are the four types of heat transfer

A

Conduction, convection, radiation, evaporation

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8
Q

Calculate the gpm for an 80 MBH heat load using water as the HTF with a delta T of 20 degrees

A

8 gpm BTUH=500x specific heat x Delta T

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9
Q

How is TEL (Total equivalent length) meassured and calculated

A

Measure longest circuit and add 50% for fittings and terminal units

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10
Q

which type of heat, when added or removed from a substance creates a change of state?

A

Latent heat

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11
Q

Define humidity

A

The amount of moisture in the air

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12
Q

What is the dry bulb temperature

A

Temperature of air taken with a standard thermometer

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13
Q

which tool is used to determine relative humidity

A

Sling phychrometer

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14
Q

How is the rate of flow measured

A

gallons per minute

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15
Q

select three types of heat transfer

A

Radiation convection conduction

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16
Q

Any pressure above a perfect vacuum is measured as

A

Psia

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17
Q

What is atmospheric pressure at sea level

A

14.7 psia

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18
Q

Temperature comfort is accomplished by controlling

A

Temperature and humidity

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19
Q

Room humidity is measured with a

A

Hygrometer

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20
Q

Describe enthalpy

A

Total amount of energy of a substance

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21
Q

Select the best statement regarding thermal conduction through and object or substance

A

Transfer of heat happens when both materials are in contact

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22
Q

What is another term for pump capacity

A

head pressure

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23
Q

Evaporation occurs when water absorbs _____ heat

A

Latent

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24
Q

by controlling the rate of _____, hydronic heating and cooling systems allow the body to be comfortable

A

Heat loss

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25
Q

What is absolute pressure

A

Gauge plus atmospheric pressure

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26
Q

what is the formula for calculating pump gpm

A

heat loss divided by 10,000

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27
Q

What is the general equation for calculating sensible heat change of fluids

A

Btu= gpm x s x delta t x 500

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28
Q

How is vacuum measured

A

In Hg

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29
Q

What is the maximum design pressure for a low temperature boiler

A

160psig steam is 15psig

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30
Q

Select the correct valve that would be used to regulate the rate of HTF flow in a pipping system

A

balancing valve

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31
Q

Name four main components of a chiller system

A

compressor condenser, evaporator, refrigerant

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32
Q

Select the devices which would be included in a make up water system

A

pressure reducing valve, backflow, isolation

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33
Q

select the best description of a LWCO

A

low water cut off

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34
Q

which boiler has the highest output rating

A

electric

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35
Q

what device is used to protect a potable water system from cross contamination

A

backflow preventer

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36
Q

a condenser acts as a type of

A

heat exchanger

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37
Q

low pressure boilers are classified by

A

type of construction

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38
Q

Low pressure boilers have specific pressure and temperature limits, what is the maximum pressure temperature limit for these boilers

A

15psig for steam, 160psig for water @ 250 degrees

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39
Q

Which type of device is attached to the boiler to assist in the management of air in the hydronic system

A

boiler fitting

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40
Q

Which type of boiler uses a microprocessor controlled combustion which automatically adjust air fuel mixture

A

condensing

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41
Q

which device protects the boiler from pressures above maximum design pressure

A

Relief valve

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42
Q

fuel oil burner _____ fuel oil to increase contact with combustion air for maximum effciency

A

atomize

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43
Q

What does ASME boiler pressure Vessel Code require if the output of a boiler is 400,000 BTUH or

A

LWCO

44
Q

An output rating is the total amount of heat a boiler will produce in

A

one hour

45
Q

What is the device that can be used to both heat and cool and area

A

heat pump

46
Q

When a heat pump is in cooling mode the outdoor device is

A

The condenser

47
Q

As a vapor is compressed in a compression refrigeration system what happens to the refrigerant

A

Temperature increases

48
Q

In a compression refrigeration system, where is the heat absorbed

A

Evaporator

49
Q

The hydronic cooling cycle is composed of _____ seperate and distinct cycles that create the complete system

A

5

50
Q

what type of flow has better heat transfer in a coil

A

Counterflow

51
Q

a ROT can be used to calculate fill pressure of a hydronic system, when using the ROT what is considered a standard height per floor

A

10

52
Q

What are the three functions of a triple duty valve

A

Flow control, check valve, isolation

53
Q

Which impeller is most efficient for pumping clear liquids

A

vane and paddle

54
Q

how many pipe diameters of straight pipe do you need between the wye strainer and the pump

A

5

55
Q

which consideration is most important when starting a pump for the first time

A

check alignment of pump and motor

56
Q

pumps, when subjected to lift task must be _____ before starting the motor

A

primed

57
Q

Which term describes an impeller that has vanes attached to a hub that is not enclosed or supported by a shroud on either side

A

Open impeller

58
Q

which term describes a hydronic system that is sealed to prevent the entrance of air from the atmosphere

A

closed system

59
Q

why is glycol not used at 100 percent concentration

A

very high viscosity

60
Q

which pump is used most often for a closed hydronic piping system

A

centrifugal

61
Q

In a primary secondary pumping arrangement where is the largest circulator installed

A

Primary loop

62
Q

A hydronic system uses _____ to transfer heat

A

HTF

63
Q

Where would you install a triple duty valve

A

Discharge side of the circulator

64
Q

What is the maximum spacing recommended for the closely spaced tees on a primary secondary system

A

4 pipe diameters

65
Q

What are the two types of pump misalignment that must be checked

A

Angular and parallel

66
Q

What is the violent action of a vapor bubbles in a centrifugal pump

A

Cavitation

67
Q

When calculating pump capacity in an open system you must

A

Add static head to piping resistance

68
Q

A pump is not moving any flued, what should you check

A

pump is primed

69
Q

What is the maximum theoretical lift of a pump

A

34 feet

70
Q

The best place for air separation is the at the boiler, why

A

HTF is at a high temperature and low velocity

71
Q

A typical pressure at the top of a hydronic system with the pumps off would be

A

4psig

72
Q

A system is seven stories tall and it includes a captive diaphragm expansion tank in the basement what is the adjusted tank pressure? (10 feet per floor)

A

36 psig

73
Q

Select three ways air can exist withing a hydronic system

A

Air pockets, entrained air bubbles, dissolved gases

74
Q

A closed hydronic system has a static head of 30 feet. What is the cold fille pressure at the pump

A

17psig

75
Q

Which of the following flow rates is best for air removal

A

2 fps

76
Q

Which location is preferred when connectiing a pre charged expansion tank

A

Suction side of the pump

77
Q

A properly installed closed loop hydronic system that has been filled and properly maintained ______ needs additional HTF

A

Rarely

78
Q

What is the total pitch for a pipe connecting a compression expansion tank that is 5 feet long

A

1”

79
Q

Which one of these devices is an example of a final control

A

Zone valve

80
Q

Which check valve relies on a hinged disk within the valve body

A

swing check

81
Q

what is used to relieve trapped air ina hydronic system

A

Air Vent

82
Q

Which fitting or device is used in a one pipe system to induce HTF flow into another pipe

A

Diversion fitting

83
Q

combination balancing and purge valves have four basic functions which of these choices is not a function of this device

A

Temperature

84
Q

what is another name for a Venturi tee

A

Diversion tee

85
Q

what is an ASTM standard for steel pipe

A

ASTM A53

86
Q

Descibe a full way valve used to regulate flow in which a threaded stem raises and lowers a wedge shaped disc

A

gate valve

87
Q

Which valve allows fluid flow in one direction

A

check valve

88
Q

Copper is often used in hydronic and refrigeration systems, list the three types of copper tubing in order of wall thickness

A

K,L,M

89
Q

A U shaped section of piping that absorbs thermal movement is a

A

Expansion Loop

90
Q

What is the maximum horizontal hanger spacing for 3 inch polypropylene pipe

A

4 feet

91
Q

_____ prevent piping in horizontal runs from sagging and leaking

A

hangers

92
Q

Select the best application for a globe valve in a hydronic piping system

A

Throttling or flow control

93
Q

Example 20’ high water column time .433 is how many psig

A

8.66 or 9psig

94
Q

8.66psig times 2.31 is how any feet of head

A

20 feet of head

95
Q

How many BTUs are required to change one pound of water at 212 degrees to steam

A

970

96
Q

when connecting the makeup water fill line, what is the best location for installation

A

point of no pressure change

97
Q

A building is 19 floors, each floor is 12 feet, pumps on first floor, what is the psi you should charge the system to in order to correctly charge with 4 psi at the top floor

A

228’ x .433= 98.7psi + 4= 102.7

98
Q

which piping system is identified by first supplied last to connect to the return

A

Direct return

99
Q

what is a zone

A

a circuit that is controlled by one thermostat

100
Q

When using an eccentric reducer in a hydronic system, how is the fitting installed

A

flat on top to keep the air moving

101
Q

Which rule applies to the branch takeoffs when piping terminal units on a one pipe system

A

should be the same width of the terminal unit

102
Q

To prevent debris from collecting in the heat transfer units how is the branch piping installed

A

top or 45 off of main

103
Q

Which system has separate heating and cooling functions with dedicated supply and return piping

A

four pipe

104
Q

which piping designs are two pipe systems

A

direct return and reverse return

105
Q

which type of fiting is used to reduce the pipe size in a hydronic horizontal main

A

Eccentric

106
Q

what are the two types of one pipe system

A

single main, series loop

UA Star Exam (3 decks)

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