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UA HVAC Star Exam Prep > UA Local 140 Practice Test 2 > Flashcards

UA Local 140 Practice Test 2 Flashcards

1
Q

In the hot gas bypass control method, which system component is bypassed?

A

condenser

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2
Q

The purpose of combustion testing is to perform all EXCEPT which of the following?

A

condition air through the air handler

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3
Q

The purpose of combustion testing is to perform all EXCEPT which of the following?

A

two dissimilar metals welded together

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4
Q

Which system component is used to prevent all strip heaters from energizing at the same time?

A

sequencer

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5
Q

What is the temperature rise across a warm air heat exchanger that is outputing 150,000 Btu’s with 2,000 CFM flowing across the heat exchanger?

A

69 Degrees

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6
Q

What is the acceptable voltage output of a thermocouple in a standing pilot boiler?

A

20-30 mV

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7
Q

. Which boiler can be brought through standard doorways and assembled in place?

A

cast iron sectional

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8
Q

What is needed in a hot water boiler to allow for the expansion of water?

A

a compression/expansion tank

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9
Q

To prevent priming in a steam boiler, the horizontal steam main should be a minimum of what distance above the NOWL?

A

24 inches

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10
Q

Normal maintenance of a gas fired burner includes all EXCEPT which of the following?

A

drilling out gas orifices

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11
Q

The boiler should____while testing low water cutoff safeties

A

automatically shut down

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12
Q

Follow which of these methods when adjusting a gas regulator to increase outlet pressure?

A

adjust clockwise to increase

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13
Q

When starting a boiler, the technician finds that the burner mainfold pressure is below normal, but with the burner “off’ the gas supply pressure is normal. What may be the problem?

A

a clogged regulator vent line

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14
Q

What is the kW rating of the following heating element?

A

3.8 kw

Volts2/ohms

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15
Q

Which of the following components is used to prove fan operation before electric duct heaters are energized?

A

sail switch

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16
Q

Which of the following is NOT a benifit of using an SCR type electric resistance heater controller?

A

reduced installation cost

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17
Q

Which of these instruments is used to measure the pressure in a naturally vented stack?

A

draft gauge

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18
Q

In starting up a chilled water system, which should be the first piece of equipment to start?

A

chilled water pump

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19
Q

What is the proper fill pressure for a system that is 100 ft above the PRV?

A

47 psig

.47 per ft

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20
Q

What is the purpose of adding glycol to a solar heating system?

A

Allow adequate freeze protection

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21
Q

Which of these is the part of the centrifugal pump that spins and forces water through the system?

A

impeller

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22
Q

Which of these is NOT a step that should be taken before starting a pump?

A

remove coupled guard

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23
Q

Which of the following is not a symptom of a water logged expansion tank?

A

erratic burner operation

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24
Q

On centrifugal pumps, if it is necessary to reduce pump flow temporarily, do so using which method?

A

throttle the discharge

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25
Q

Which instrument is needed to check the freeze protection level of a solar hydronic system?

A

refractometer

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26
Q

The water loop on a water-to-ground geothermal loop is typically made out of which type of material?

A

PVC

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27
Q

Basic types of heat pumps, classified as their heat source and the medium being heated, include all EXCEPT

A

water to air to water

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28
Q

On a water source heat pump, the refrigerant circuit has a lower than normal discharge pressure and a higher than normal suction pressure. Which is most likely the defective part?

A

reversing valve

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29
Q

Higher than normal water loop temperature would lead to which of the following conditions?

A

high subcooling

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30
Q

Higher than normal water loop temperature would lead to which of the following conditions?

A

boiler to ignite

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31
Q

A system containing one cooling tower, one water cooled condenser, and one pump is classified as which
type of system?

A

closed

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32
Q

A water coil generally should be piped to provide flow.

A

counter

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33
Q

If the water flow to a water cooled condenser is reduced, what will happen to the temperature difference across the condenser?

A

it will increase

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34
Q

A thermostatic steam strap that fails in a closed position may cause which problem to a heating unit?

A

water logged

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35
Q

Thermostatic traps are opened and closed by which device

A

flexible bellows

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36
Q

Which of the following is not a type of steam trap

A

mechanical

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37
Q

what is the purpose of a bypass on a steam regulator

A

maintains steam pressure if the regulator fails

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38
Q

which of the following is not a type of steam regulator

A

electric

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39
Q

Which of these conditions could result from condensate in steam lines?

A

water hammer

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40
Q

What is the purpose for installing a vacuum breaker valve in an automatically controlled steam heating system?

A

it limits the vacuum to the pump and prevents vacuum to the system

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41
Q

Flash tanks utilize which of the following?

A

condensate

42
Q

Which of these causes a boiler feed pump to cycle “on”?

A

boiler feed pump controller

43
Q

To which location are condensate return systems vented?

A

atmosphere

44
Q

Which of these components is needed on the discharge side of a condensate return pump to ensure no backflow of condensate into the tank

A

double check valve

45
Q

What length of pipe (drip connection) is needed to overcome pressure drop in a one pipe, gravity return steam heating system and return condensate to the boiler?

A

28 inches

46
Q

Which type of connection is used to connect the boiler return line to the steam main?

A

Hartford loop

47
Q

What will happen to a constant volume squirrel cage fan if you restrict the air flow to the fanas, for example, when filters become dirty?

A

the fan motor amperage will decrease

48
Q

Mixing boxes are usually used with which type(s) of system?

A

double duct system

49
Q

Which unit of measure is used to express the velocity of air in a duct?

A

ft/min

50
Q

Which of the following is not a basic type of air supply outlet?

A

barometric damper

51
Q

An air distribution system increases comfort of occupants by controlling al EXCEPT

A

kw consumption

52
Q

Which of these events may be caused by a dirty heat recovery heat exchanger?

A

excessive loads on A/C system

53
Q

Which scenario would justify the addition of a heat recovery unit?

A

a building needs outside makeup air but HVAC equipment is marginally sized

54
Q

Which of the following statements is NOT true of a desiccant type heat recovery system?

A

it created high loads than traditional airside economizers

55
Q

In an air conditioning system, free cooling is so called because it eliminates operating the
while still meeting cooling needs.

A

compressor

56
Q

In an air conditioning system, free cooling is so called because it eliminates operating the
while still meeting cooling needs.

A

opposed

57
Q

An enthalpy control in an economiser regulates the use of outdoor air on the basis of the air’s.

A

total heat

58
Q

Air conditioning systems may go into economizer mode during the ____ cycle.

A

cooling

59
Q

when performing routine maintenance on an economizer, which of the following items do not need to be checked?

A

cooling anticipator

60
Q

Why is it desirable to have a pressure differential gauge to measure filter resistance?

A

to tell when the filters are dirty

61
Q

which of these is an instrument to be inserted into a duct for measuring velocity pressure

A

pitot tube

62
Q

Which control should be installed on an air handler which brings in outside air through a steam coil?

A

freeze stat

63
Q

For systems with VAV control, what device is needed for proper operation?

A

static pressure sensor

64
Q

When copper tubing is being brazed, nitrogen gas can be purged through the system to prevent which of these events?

A

oxidation inside the tubing

65
Q

When using an oxy-acetylene torch for brazing, the flame should be adjusted to provide a(n)

A

neutral

66
Q

When soldering copper tube, after the tube and fitting are cleaned and fluxed, how soon should they be soldered?

A

as soon as possible

67
Q

if NOT properly installed, a compressors discharge muffler malfunction in this way.

A

trap oil

68
Q

When using a capacity control compressor, which of these is a requirement for double suction gas risers?

A

allow for oil return to compressor during low load conditions

69
Q

Condensate drain traps are required on draw-through evaporator coils in order to prevent which of the
following conditions from occuring?

A

water overflow

70
Q

If NOT properly installed, a hot as muffler might trap which of the following?

A

oil

71
Q

With reference to copper tube, what is meant by the initials ACR?

A

air conditioning and refrigeration

72
Q

Residential air conditioning piping should be sized according to which of these?

A

manufacturing instructions

73
Q

Which of these may be caused by an oversized vapor line in a refrigerant circuit?

A

poor oil return

74
Q

On a refrigeration system where the evaporator is located below the compressor, how are suction risers sized?

A

smaller for high velocity

75
Q

When connecting rigging to equipment, where should the connection be made?

A

per equipment manufacturers instructions

76
Q

What is the meaning of the crane signaler’s hand when pointed toward the ground with his/her finger moving
in a circle?

A

lower load

77
Q

When choking a piece of equipment with a sling, where should you run the sling?

A

through the clevis attached to the eye

78
Q

Which is true when a load is to be lifted with a sling?

A

all sharp edges should be padded

79
Q

Which of the following is NOT correct when working

A

use grease or oil on the hose and regulator threaded connections

80
Q

What does CPR stand for?

A

Cardio Pulmanary Resuscitation

81
Q

Energized electrical equipment or “live” equipment is dangerous. How does OSHA suggest the worker should deal with this potential hazard?

A

b. inspect and test all equipment, assuming d. all to be energized until proven
de-energized

82
Q

Why are the frames of electrical devices grounded?

A

to maintain the frame at zero potential to ground

83
Q

Which organization or department enforces the regulations of the Clean Air Act?

A

EPA

84
Q

Which of the following government agencies is responsible for the regulations dealing with the transportation of hazardous material?

A

DOT

85
Q

Which of the following government agencies regulates the certification of refrigerant cylinders?

A

DOT

86
Q

Which of these is an example of a halogen?

A

CFC refrigerants

87
Q

Which of these should be worn to protect the eyes when handling refrigerants?

A

chemical splash goggles

88
Q

A cylinder recovery tank with a service rating of DOT psig is required for R410A.

A

400

89
Q

If the air velocity in a 10” x 20” duct was found to be 2,000 FPM, how many CFM of air would be moving

A

2777 cfm

10x20/144x 2000fpm=2777

90
Q

A rectangular duct measures 20” x 30”. What is the area in square feet?

A

4.167

20x30/144=4.167

91
Q
  1. When circulating water is cooled in a chiller, the heat of the water is changed.
A

sensible

92
Q

What is the atmospheric pressure at seal level?

A

14.7psia

93
Q

Which is true of the refrigerant in the evaporator?

A

it removes both latent heat and sensible heat from the air passing over

94
Q
  1. The symbol shown here is used to indicate a actuated switch that on a rising signal.
A

pressure, closes

95
Q

When performing routine preventative maintenance it is important to document all EXCEPT which of the following pieces of information?

A

customers age and sex

96
Q

Where does good recordkeeping start?

A

with field technicians

97
Q

Your first service call was servicing an oil furnace located under a house. Before proceeding to the next call, a thermostat installation, you should

A

change into clean uniform

98
Q

Once an oral agreement has been made with a customer, it is important to do what?

A

make a note to yourself

99
Q

When writing a proposal, always be sure to include which of the following?

A

the contractors cost

100
Q

What should you do if a customer refuses to sign a work order?

A

note it on the ticket and call your supervisor

UA HVAC Star Exam Prep (4 decks)

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