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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
Which instrument is needed to check the freeze protection level of a solar hydronic system?
refractometer
26
The water loop on a water-to-ground geothermal loop is typically made out of which type of material?
PVC
27
Basic types of heat pumps, classified as their heat source and the medium being heated, include all EXCEPT
water to air to water
28
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?
reversing valve
29
Higher than normal water loop temperature would lead to which of the following conditions?
high subcooling
30
Higher than normal water loop temperature would lead to which of the following conditions?
boiler to ignite
31
A system containing one cooling tower, one water cooled condenser, and one pump is classified as which type of system?
closed
32
A water coil generally should be piped to provide flow.
counter
33
If the water flow to a water cooled condenser is reduced, what will happen to the temperature difference across the condenser?
it will increase
34
A thermostatic steam strap that fails in a closed position may cause which problem to a heating unit?
water logged
35
Thermostatic traps are opened and closed by which device
flexible bellows
36
Which of the following is not a type of steam trap
mechanical
37
what is the purpose of a bypass on a steam regulator
maintains steam pressure if the regulator fails
38
which of the following is not a type of steam regulator
electric
39
Which of these conditions could result from condensate in steam lines?
water hammer
40
What is the purpose for installing a vacuum breaker valve in an automatically controlled steam heating system?
it limits the vacuum to the pump and prevents vacuum to the system
41
Flash tanks utilize which of the following?
condensate
42
Which of these causes a boiler feed pump to cycle "on"?
boiler feed pump controller
43
To which location are condensate return systems vented?
atmosphere
44
Which of these components is needed on the discharge side of a condensate return pump to ensure no backflow of condensate into the tank
double check valve
45
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?
28 inches
46
Which type of connection is used to connect the boiler return line to the steam main?
Hartford loop
47
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?
the fan motor amperage will decrease
48
Mixing boxes are usually used with which type(s) of system?
double duct system
49
Which unit of measure is used to express the velocity of air in a duct?
ft/min
50
Which of the following is not a basic type of air supply outlet?
barometric damper
51
An air distribution system increases comfort of occupants by controlling al EXCEPT
kw consumption
52
Which of these events may be caused by a dirty heat recovery heat exchanger?
excessive loads on A/C system
53
Which scenario would justify the addition of a heat recovery unit?
a building needs outside makeup air but HVAC equipment is marginally sized
54
Which of the following statements is NOT true of a desiccant type heat recovery system?
it created high loads than traditional airside economizers
55
In an air conditioning system, free cooling is so called because it eliminates operating the while still meeting cooling needs.
compressor
56
In an air conditioning system, free cooling is so called because it eliminates operating the while still meeting cooling needs.
opposed
57
An enthalpy control in an economiser regulates the use of outdoor air on the basis of the air's.
total heat
58
Air conditioning systems may go into economizer mode during the ____ cycle.
cooling
59
when performing routine maintenance on an economizer, which of the following items do not need to be checked?
cooling anticipator
60
Why is it desirable to have a pressure differential gauge to measure filter resistance?
to tell when the filters are dirty
61
which of these is an instrument to be inserted into a duct for measuring velocity pressure
pitot tube
62
Which control should be installed on an air handler which brings in outside air through a steam coil?
freeze stat
63
For systems with VAV control, what device is needed for proper operation?
static pressure sensor
64
When copper tubing is being brazed, nitrogen gas can be purged through the system to prevent which of these events?
oxidation inside the tubing
65
When using an oxy-acetylene torch for brazing, the flame should be adjusted to provide a(n)
neutral
66
When soldering copper tube, after the tube and fitting are cleaned and fluxed, how soon should they be soldered?
as soon as possible
67
if NOT properly installed, a compressors discharge muffler malfunction in this way.
trap oil
68
When using a capacity control compressor, which of these is a requirement for double suction gas risers?
allow for oil return to compressor during low load conditions
69
Condensate drain traps are required on draw-through evaporator coils in order to prevent which of the following conditions from occuring?
water overflow
70
If NOT properly installed, a hot as muffler might trap which of the following?
oil
71
With reference to copper tube, what is meant by the initials ACR?
air conditioning and refrigeration
72
Residential air conditioning piping should be sized according to which of these?
manufacturing instructions
73
Which of these may be caused by an oversized vapor line in a refrigerant circuit?
poor oil return
74
On a refrigeration system where the evaporator is located below the compressor, how are suction risers sized?
smaller for high velocity
75
When connecting rigging to equipment, where should the connection be made?
per equipment manufacturers instructions
76
What is the meaning of the crane signaler's hand when pointed toward the ground with his/her finger moving in a circle?
lower load
77
When choking a piece of equipment with a sling, where should you run the sling?
through the clevis attached to the eye
78
Which is true when a load is to be lifted with a sling?
all sharp edges should be padded
79
Which of the following is NOT correct when working
use grease or oil on the hose and regulator threaded connections
80
What does CPR stand for?
Cardio Pulmanary Resuscitation
81
Energized electrical equipment or "live" equipment is dangerous. How does OSHA suggest the worker should deal with this potential hazard?
b. inspect and test all equipment, assuming d. all to be energized until proven de-energized
82
Why are the frames of electrical devices grounded?
to maintain the frame at zero potential to ground
83
Which organization or department enforces the regulations of the Clean Air Act?
EPA
84
Which of the following government agencies is responsible for the regulations dealing with the transportation of hazardous material?
DOT
85
Which of the following government agencies regulates the certification of refrigerant cylinders?
DOT
86
Which of these is an example of a halogen?
CFC refrigerants
87
Which of these should be worn to protect the eyes when handling refrigerants?
chemical splash goggles
88
A cylinder recovery tank with a service rating of DOT psig is required for R410A.
400
89
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
2777 cfm 10x20/144x 2000fpm=2777
90
A rectangular duct measures 20" x 30". What is the area in square feet?
4.167 20x30/144=4.167
91
91. When circulating water is cooled in a chiller, the heat of the water is changed.
sensible
92
What is the atmospheric pressure at seal level?
14.7psia
93
Which is true of the refrigerant in the evaporator?
it removes both latent heat and sensible heat from the air passing over
94
94. The symbol shown here is used to indicate a actuated switch that on a rising signal.
pressure, closes
95
When performing routine preventative maintenance it is important to document all EXCEPT which of the following pieces of information?
customers age and sex
96
Where does good recordkeeping start?
with field technicians
97
Your first service call was servicing an oil furnace located under a house. Before proceeding to the next call, a thermostat installation, you should
change into clean uniform
98
Once an oral agreement has been made with a customer, it is important to do what?
make a note to yourself
99
When writing a proposal, always be sure to include which of the following?
the contractors cost
100
What should you do if a customer refuses to sign a work order?
note it on the ticket and call your supervisor

UA HVAC Star Exam Prep (4 decks)

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