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Nocti Hvac study guide Questions and Correct
Answers
An Hvac system that depends on the temperatures below the ground surface as an
operation factor is a ..
✓ ~~~ Geothermal heat pump
when putting out a fire involving oily rags use a ________ fire extinguisher?
✓ ~~~ Class B
The best tool to open and close the stem access valve on a refrigeriation system is
the_______
✓ ~~~ Refrigeration service wrench
Which power tool is best to cut steel rod?
✓ ~~~ Sawzall
CSST (steal tubing) connections
✓ ~~~ can be used with both natural and propane gas equipment
The type of pipe commonly used for condensation drainage on central air
conditioning system is
✓ ~~~ PVC
When pressure testing completed copper tubing assembly with pressuried nitrogen
the nitrogen cylinder should
✓ ~~~ always be on the ground
connections should be permanently connected with_____ on drainage piping
assemblies that uses PVC piping
✓ ~~~ Glue specified for PVC pipe
Using oxygen to purge copper tubing after brasing
✓ ~~~ could cause and explosion
Two gases that considered non-condensable in a refrigeration
✓ ~~~ Air and Nitrogen
Residential air condition system have a super heat range of ____ degress under
normal operating conditions?
✓ ~~~ 8 to 12
which is not a condition of low superheat on an air conditioning system
✓ ~~~ Refrigerant undercharged
The reason that subcooling would be below 8 degrees on air conditiong system
✓ ~~~ dirty or blocked condenser coil
when pressure testing a completed copper tubing assembly with pressurized nitrgen
cylinders should
✓ ~~~ always be used with a regulator
a 14-gauge soild copper wire would require____amp circuit protection
✓ ~~~ 15 amps
in a 24V circuit containing a switch and coil, it will read 24V at the coil if the
✓ ~~~ switched is closed
A theremocouple produces _______ when heat is applied
✓ ~~~ DC voltage
in 120VC AC circuit, if the total circuit draws 5 amps the wattage is
Capacitors are rated in
✓ ~~~ Volts and micro farads
The refrigerant enter the condenser as a
✓ ~~~ High pressure vapor
the compressor's main function is to
✓ ~~~ create presssure diffrence
scroll compressors are cooled by Ac and
✓ ~~~ Suction vaper
what tool is used to check the gas pressure
✓ ~~~ Manometers
incomplete combustion produces
✓ ~~~ carbon monoxide
a sub- base of a T-stat should be mounted
✓ ~~~ level
For complete combustion in a boiler or furnance to occur,_______ should _____ be
present
✓ ~~~ Oxygen, Spark, and fuel
Its recomended that mainatence on an oil boiler or furance be performed every...
✓ ~~~ Year
which of these organization requires approved footwear on job sites?
✓ ~~~ ANSI
A heat pump designed to work for both heating and cooling. which device changes
the flow of the refregeriant for each mode?
✓ ~~~ reversing valve
Initation defrost in a heat pump system can be done by the flowing method timed,
electronic board, and
✓ ~~~ Temperature
the permanent storage device found inside a desktop computer is a
✓ ~~~ hard drive
One chlorine atom can destroy how many ozone molecules?
bad ozone is found in which of the following
✓ ~~~ troposphere
which refrigersant types have a very low GWP?
✓ ~~~ HFC
which type of oil is used in modern automotive air conditioning system?
✓ ~~~ Glycols
what year did it become necessary for all hvac technitions to become certified to
handle refrigerant under section 608 for thr clean air act?
which is not a health risk associted with the ozone depleation
✓ ~~~ lung cancer
which refrgrant type of experiance the largest temperature glides?
✓ ~~~ Zoetrope's
The most commonly known CFC Refrigrant?
✓ ~~~ R- 12
if the operating pressures are 90 psih on the low side and 250 psig on the high side
what would be the problem?
✓ ~~~ ineffcient compressor
what year did it become unlawful to knowingly vent CFC and HCFCs?
The process od the removing refrigerant from an air conditioning system and storing
it in an external container?
✓ ~~~ Recovery
The easiest way to move equipment across a roof is to use
✓ ~~~ plywood and rollers
power tools that are not double insulted must have three prong plugs to ensure that
the tool is properly
✓ ~~~ grounded
the tool used to create internal threads is called a
✓ ~~~ tap
the tool to creat pipe threads on the outside of a pipe is called a
✓ ~~~ die
Fires that involve ordinary materials such as paper, cardboard, and wood are
classified as Type __________ fires.
✓ ~~~ A fires
In the electrical circuits, the _____ wire protects the operator
✓ ~~~ Grounding
Fires that involve electrical equipment are classified as Type _____ fires.
✓ ~~~ Type c fires
electrical power should always be shut off at the ____ or entrance panel and locked
in an approved manner when installing equipment
✓ ~~~ distribuation
a ________ is used to measure the amount of CO2 in the flue product
✓ ~~~ CO2/O2 indicator
After brazing a joint in a very tight location, the technician would use a(n)
__________ to determine if the joint is properly brazed.
✓ ~~~ Inspection mirror
the dial-type meter used to measure the pressure in a heating unit flue pipe is called
a
✓ ~~~ cordless drill
evacuting a system is accomplishedwith an _____ and helps to remove air and non-
conditioning and refrgeration applications
✓ ~~~ screw compressor
the four major components of a vapor compression refrigeration system are the
compressor, condenser, evaporator and
✓ ~~~ Metering Device
From a performance standpoint, a substitute for R- 1 2 is ______.
✓ ~~~ heat moves towards a place with lower intensity
sensible heat describes
✓ ~~~ how hot something feels
latent heat measures
✓ ~~~ The heat potential of a substance.
latent heat is measured in
✓ ~~~ britsh thermal units
If 1 pound of water warms to 60 degrees F from 55 degrees F, what btu of latent
heat will it have absorbed?
what is the amount of heat energy required to evaporate 1 pound of water
✓ ~~~ 970 BTU
in an air conditioning and refrigeration system=, what occurs in an evaporater?
✓ ~~~ The refrigerant asborbs the lantent heat
in an air conditioning and refrigeration system what occurs in a condenser?
✓ ~~~ the refrigerant releases the latent heat
in sealed system, pressure and temperature
✓ ~~~ follow each other up and down
which of the following is not a type of compressor?
✓ ~~~ lateral
in fahrenheit, the boiling point water is
✓ ~~~ 212 degrees
to change fahrenheit to celsius, whicb formula is used
✓ ~~~ C=(F-32)/1.
which of the following is not a method by which heat may be transferred from a
warmer substance to a colder substance?
✓ ~~~ retraction
What btu of heat is required to raise 1 pound of ice 1 degree F when the temperature
is below 32 degrees F?
What btu of heat is required to raise 1 pound of steam 1 degree F above the
temperature of 212 degrees F?
the exertion of pressure on a substance with a contant temperature increases it
volume in proportion to the increase in pressure
✓ ~~~ False
a 50/50 solder is a combination of lead and
✓ ~~~ tin
when calculating heat loss, the HTM means the
✓ ~~~ heating transfer multiplier
The refrigerant used in smaller centrifugal compressors is
✓ ~~~ R- 11
when writing a resume, its best to
✓ ~~~ accurately list education and work history
of the following_______ sliver has the highest melting point
what is the angle of the- are shoulder?
✓ ~~~ 30 degrees
all refrigerant lines that are installed horizontally should
✓ ~~~ pitched towards the compressor
when working with sharp or rough metal, the sheets metal worker should
✓ ~~~ wear gloves and thick glasses
when filling out the service invoice during a routine preventive maintance call, worker
should record the
✓ ~~~ volts and amps readings
the standard atmospheric conditions for wateer to boil at 212 degree are
✓ ~~~ atmosphere pressure 14.696 psi temp 70- degree F
at standard conditions on the celsius scale water will boil at
✓ ~~~ 100 degrees C
heat flows from warmer substanstance to a cooler substance
✓ ~~~ true
a bourdon tube is often found in a
✓ ~~~ pressure gauge
The PSIA at sea level under standard conditions is _____ psi.
a fusible plug is made from
✓ ~~~ a metal alloy that will burn when overheated
Oil must never be used around a ______ cylinder.
✓ ~~~ acetylene
the three states of matter are
✓ ~~~ solid, liquid, gas
a gas law that states the total pressure of a combined mixture is equal to the sum of
the individual pressures is
✓ ~~~ daltons law
water on the floor of the work area can
✓ ~~~ increase the chance of slipping and receiving and electric shock
rubber soled, steel toes work boots help prevent injuries involving
✓ ~~~ falling objects, and electric shock
the three components required for combustion are
✓ ~~~ fuel, Oxygen, and heat
a pressure reading of 10in W.C is approximately equal to
✓ ~~~ 0.36 psig
The ignition method that uses an eletric spark to ignite the pilot is called the
✓ ~~~ intermittent pilot
which of the following hydrocarbons make up the largest precentage of natural gas
✓ ~~~ methane
flame retention oil burners
✓ ~~~ produce a flame that is 300-500 F hotter than conventional burners
