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WorksheetsUA Star Part 2.1
Total questions: 94
Worksheet time: 47mins
the proper installation height of the Hartford loop on a steam boiler is how many inches below the NOWL?
at nowl
2-4 inches
6-10 inches
28 inches
to prevent priming in a steam boiler the horizontal steam main should be a minimum of what distance NOWL?
12 inches
24 inches
28 inches
2.31 feet
all except which of the following are flame proving methods?
diode
flame rectification
infrared
Ultraviolet
which type of ignition system uses a pilot flame?
direct spark
glow coil
hot surface ignition
intermittent
which of the following is NOT used to size gas regulators?
inlet pressure
type of ignition system
pipe size
Volume
if a gas regulator is located in the boiler room, typical code requires that the regulator vent needs to be piped where?
indoors
into the floor drain
outdoors
there is no connected piping required
electric heaters are usually composed of which of the following?
capacitors
inductors
rectifiers
resistors
What is the most likely cause if a technician finds that an electric heat element with voltage applied to the element has no current draw?
lack of air flow
low voltage to the element
open or burned element
too much voltage to the element
When replacing the element on an electric heater the technician should verify what the element(s) _______?
Are not shorted to ground
are streched as much as possible
coils are turned clockwise
Coil are turned counter clockwise
Which is an acceptable vent material for condensing boilers?
a-vent
b-vent
pvc
single wall vent
Which of these control modes does NOT provide modulating control?
derivative
integral
proportional
2 position
Why should low water cut off controls on a steam boiler be blown down routinely?
brings clean water into the steam boiler
makes room for boiler water chemical
prevent sediment buildup that would limit proper operation
removes total dissolved solids from the bottom of the boiler water
A 3 way valve having one inlet and two outlets is classified as a _______ valve.
mixing
pilot operated
two postions
Which type of valve has the best variable flow characteristics in hydronic system?
ball
butterfly
gate
globe
Which of the following is a function of the pressure reducing valve?
adds make up water to the system when needed
de-energizes the burner if the water level falls too low
maintains the desired water temperature in the system
relieves excess system pressure
Which of the following is not a result of pump cavitation?
impeller damage
increased head pressure
no change in flow
reduced head pressure
Which of the following is the most likely cause of cavitation in a pump that is pumping hot water?
decreased water flow
excessive NPSH
insufficient NPSH
noisy pump
Which of the most common pump used in hydronic systems?
centrifugal
gear
reciprocating
scroll
Installing two pumps in parallel will result in the following
decreased flow
increased flow
no change
This arrangement results in no appreciable changes therefore it is never done
What is the purpose of adding glycol to a solar heating system?
It allows adequate freeze protection in low ambient conditions
It keeps water from expanding
It maintains ability of fluid to pump even at low fluid temperatures
It minimizes corrosion in piping
Where would a ground source heat pump reject its heat load when in the cooling mode of operation?
to the ground loop
to the outside air
to the inside air
to the wastewater loop
Which device is used on a water source heat pump to maintain adequate head pressure in the refrigerant loop while in the cooling mode?
circuit setter
shut off valve
solenoid valve
water regulating valve
Higher than normal water loop temperature would lead to which of these results?
high discharge pressure
high sub-cooling
low air flow
low suction pressure
How much heat does a 10-ton water source heat pump inject into the water loop when fully loaded in the cooling mode?
12,000 btu/h
15,000 btu/h
120,000 btu/h
150,000 btu/h
What is the proper method for cleaning a tube-in-tube type condenser on a water source heat pump?
brush or mechanical cleaning
clean the strainer
chemical clean
blow out with nitrogen
Which of these is required on a four-pipe system for chilled water and hot water?
a changeover control valves
longer time for changeover than a two pipe system
only one pump
separate cooling and heating coils
A water coil generally should be piped to provide _____ flow?
counter
cross
parallel
none of the above
What is the differential pressure converted to feet of head across the following pump? 1 psi = 2.31 feet of head Suction pressure = 35 psig Discharge pressure = 62 psig
62 feet of head
80 feet of head
110 feet of head
143 feet of head
When the float rises on an F and T trap, what discharges?
Air
Air and steam
condensate and steam
non condensable
Which of these would result if the float and thermostatic trap failed and filled with water?
air would discharge continuously
condensate would discharge continuously
steam would discharge continuously
Condensate discharge would be greatly reduced
Which type of trap is normally used on a steam radiator?
disc
F & T
inverted
thermostatic
A steam pressure regulator is constructed so that a rise in ______ steam pressure reduces the flow of supply steam to maintain set point?
barometric
inlet
upstream
If used to drip the end of a steam main, which type of steam trap would require a cooling leg?
F & T
inverted bucket
thermodynamic
thermostatic
A steam coil utilizing a modulating steam control valve would require which type of trap?
F & T
inverted bucket
thermodynamic
thermostatic
A low pressure one pipe gravity return steam heating system is installed and an automatic steam trap is NOT used. Which of these devices will prevent a vacuum from forming?
air vent
atmospheric connection
safety relief valve
vacuum breaker
Which of the following is used to recover the energy that would be lost if flash steam were wasted through a vent?
flash tank
main air vent
radiator
strainer
Air is eliminated from a sub-atmospheric steam system by which of these devices?
air eliminator
air scoop
air vent
vacuum pump
How do condensate return pumps cycle "on"?
by a float switch in the condensate tank
by a boiler feed pump controller
low water condition in boiler
high pressure in boiler
Which of the following is NOT acceptable in a condensate return pump?
air
condensate
live steam
water
Condensate return lines should be made of which type of pipe?
schedule 40 carbon steel
schedule 80 carbon steel
schedule 80 PVC
type M copper
Which of these devices forms a water seal that prevents raw steam from entering and damaging pressure gauges, vapor stats, pressure controls, etc?
dip tube
pigtail
safety glass
sight glass
rpm of drive = diameter of driver x rpm of driver / diameter of driven. A belt driven fan has a 3" motor sheave pitch diameter, a 5" fan sheave pitch diameter and a motor speed of 1720 rpm. What is the fan speed?
103.2 rpm
1200 rpm
10320 rpm
The design of the air supply duct will depend on the air velocity but NOT the _______.
crf
lengh of run
pressure drop
An air distribution system increases comfort of the occupants by controlling all except which of the following?
air motion
density
humidity
temperature
In addition to drafts and condensation on ducts, which of these is potentially another undesirable effect of using very cold supply air?
icing of cooling coils
insufficient velocity pressure in ducts
outside air too warm
returning air too warm
The amount of air per ton typically delivered through the indoor coil on a properly operating cooling system should be approximately in the range of _____ CFM.
100-150
600-650
800-850
Which is true of a heat recovery unit designed for latent heat transfer?
It must have a condensate drain
It must move NOT more than 400 cfm
It must move over 400 cfm
It will require enthalpy controls
A desiccant type heat recovery system does all EXCEPT which of the following?
creates higher loads than traditional airside economizers
provides air exchange for conditioned space
provides high efficient outside air makeup
reduces the load of outside air
Which scenario would justify the addition of a heat recovery unit?
a building needs outside air makeup, but hvac equipment is marginally-sized
a heating system holds the load of a garage but has a long recovery time when overhead
a homeowner in San diego needs air makeup when running an attic fan
homeowners in North Dakota complain that their heating system does not keep up when outside air is below 100 degrees
In an air conditioning system, free cooling is so called because it eliminates the operation of which of the following?
chilled water pump
compressor
evaporator fan
furnace
A damper that must throttle air flow should have which of the following?
constant volume control
Face and bypass damper action
opposed blade operation
parallel blade operation
An economizer control contains three automatic dampers, one each for exhaust air, _____, and maximum OSA.
cold plenum
hot plenum
return air
supply air
Economizers can use several types of sensor. Which of these sensors is considered the most accurate?
enthalpy
entropy
fixed resistance
temperature
For good air circulation in an office space without undue danger of drafts, a desirable rate of air supply is within a range of how many air changes per hour?
1 to 3
5 to 8
10 to 12
14 to 18
A firestat should have which of these elements?
automatic reset
nonadjustable set point
remote adjustable set point
all of the above
Which of these may cause high duct pressure limit switches to open?
dirty air filters
electric heater stay on
fire or zone dampers close suddenly
the building is over-pressurized
When the freeze stat trips, the outside air damper, the chilled water valve, and the hot water valve should _____, respectively.
close, close, close
close, open, open
open, close, close
open, open, open
Which of these devices is needed for proper operation of a system with vav control?
sail switch
high limits switch
static pressure sensor
freeze stat
If you were on a job and ran out of fittings while installing 5/8" ACR tube, which of the following sizes of copper water tube fittings could be used?
1/2"
5/8"
3/4"
water tube fitting cannot be used with ACR tube
You are soldering copper tube. After the tube and fitting are cleaned and fluxed, it is recommended that they be soldered how soon?
anytime
asap
within 3 hours
within 24 hours
You may see which of these results if a compressor’s discharge muffler is not properly installed?
it could de-superheat the discharge vapor
it could trap non-condensables
it might increase line size
it might trap oil
What should be the pitch of horizontal suction refrigeration piping runs?
toward the compressor
away from the compressor
in the opposite direction of flow
they should be level
Condensate drain traps must be used on draw-through evaporator coils in order to prevent which of the following conditions?
Drain pipe freezing
high air resistance
low static pressure
water overflow
Which of these is true of the wall thickness of type K copper tube?
It is greater than type L or type M
It is less than type L but greater than type M
It is less than type M but greater than type L
It is the same as ACR hard-tempered tube
When copper tubing is being brazed, nitrogen gas can be purged through the system to prevent which of the following conditions?
damage to the temperature sensitive components
overheating the tubing
oxidation inside the tubing
production of toxic fumes
Steam branch line connection should be made from the ________ of the steam main.
bottom
side
top
location is at the installer's discretion
Which of these may be caused by an undersized vapor line in a refrigerant circuit?
decrease sub-cooling
excessive pressure drop
increased sub-cooling
poor oil return
On a refrigeration system where the evaporator is located below the compressor suction, how are risers sized?
larger for higher velocity
larger for low pressure drop
smaller for higher velocity
smaller for low pressure drop
Which of these is true when a load is to be lifted with a sling?
all sharp edges should be padded
slight damage to the sling is acceptable
the sling strength is irrelevant
all of the above
What should be done with defective rigging components and hardware?
recycle
remove from service
repair
wash
When connecting rigging to equipment, where should the connection be made?
at the top
basket only
only at the corners
connect according to equipment manufacturer's instructions
Which of the four lifting sling configurations shown here creates the greatest amount of load strain on the sling?
(Medium angle
(Shallow angle)
(Steep angel)
Straight
Which method should be used with lifting heavy objects from the floor?
lift with straight legs and a bent back
lift with straight legs and bent arms
lift with the back, not the legs
lift with the legs, not the back
Which federal agency is responsible for personnel safety?
DOT
EPA
NFPA
OSHA
When conducting certification of lockout procedures, which of the following observations would trigger the need for re-training?
The operator uses a hasp to allow lockout by more than one person
The operator informs other in the area about lockout
An identification tag is placed on the lock
None of the above
After opening the disconnect, a service technician must first ________ to confirm that there is no power present.
Confirm that there is no power
Notify customer that the power is off
install lockout/tag out on disconnect
install lock out/ tagout device
The clean air act regulations are enforced by which of these government agencies?
Department of commerce
DOT
EEDC
EPA
Which of these government agencies regulates the certification of refrigerant cylinders?
DOT
EPA
FTC
OSHA
What is the definition of "de minimus"?
5 ounces
Legal term for minimum amount
Minimum vacuum pressure
What your gauge set holds
When handling refrigerants, what protection is required for your eyes?
#4 brazing lens
Chemical/splash goggles
Contact lenses
Eye protection is not required
How should skin that comes in contact with liquid refrigerant be treated?
As a scald
As frostbite
As a burn
As bruising
A cylinder recovery tank with a DOT service rating of ____ psig is required for r410a.
100
200
300
400
What is a pump's maximum theoretical lift?
433lbs/ft head
4ft hd/lb
29.92 ft
34 ft
Choose the form of water with the largest in BTU per pound.
latent heat of fusion
latent heat of melting
latent heat of vaporization
sensible heat
How many BTUs are absorbed by the water when one pound of water at 212 degrees F?
zero
144
180
970.3
How would Terminals "A" be labeled?
Terminals connected to line side
H1, H2, H3
L1, L2, L3
T1, T2, T3
X1, X2, X3
Which of the following is NOT a required part of the word order?
a complete list of materials used
clear and legible handwritten information
amount of time spent on the job
wholesale cost of parts used
When contacting a manufacturer regarding packaged parts for a roof top unit, which of these is the most important piece of information to have available?
date of manufacture
job site address
model and serial number
voltage
Which of the following is NOT your responsibility relative to your work crew?
Getting to work on time and working effectively during your shift
keeping to yourself and not bothering others
presenting a good appearance and being enthusiastic and cooperative on the job
working safely at the worksite
Which of the following is true of a dirty and unkempt service van?
It improves work efficiency
It is normal for a service technician
It is unprofessional and inefficient
It represents a professional image for the company
What is the last thing you should do before leaving the job?
Clean the job site
Cost out the job
Have the work order signed
Place all panels back into position
Worn sleeve bearings can be quickly checked by which of these methods?
Check the centrifugal switch points
Check the squirrel cage rotor
Check the stator
Try to move the shaft at right angles to the bearing
Which type of coupling is shown here?
Looks like a tire
Chain
Gear
Soft torque (tire type)
Spider gear
Which type of flexible coupling insert is shown here?
Looks like a spider
Chain
Flange type
Gear type
Spider
