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WorksheetsHeat Pumps Midterm
Total questions: 77
Worksheet time: 39mins
When working in a machine room, safety glasses should not be worn because they can fog up and impede your eyesight.
True
False
Electrical power should always be shut off at the _____ or entrance panel and locked out in an approved manner when installing equipment.
equipment
local
distribution
remote
Fire extinguishers that can be used on any type of fire, A, B, or C generally contain a _____ to extinguish the fire.
water
carbon dioxide
nitrogen
dry chemical powder
Oil must never be used around a(n) ____________________ cylinder.
oxygen
nitrogen
carbon monoxide
helium
Power tools that are not double insulated must have three-prong plugs to ensure that the tool is properly ____________________.
floored
grounded
winded
A cylinder with 1,500 sq. in. of internal surface contains R-22 and is in a service truck body at 120°F. What is the total outward force of the refrigerant against the inner wall of the cylinder in tons of pressure?
202.64
226.61
194.92
145.71
Which of the following statements is correct when referring to large refrigerant or nitrogen tanks?
The protective cap must be on when the tank is not in use.
Safety goggles or glasses must be worn when moving the tank.
Large tanks should not be carried, they should be secured to an approved cart.
All of the above are correct.
Which of the following statements is correct when referring to large refrigerant or nitrogen tanks?
The protective cap must be on when the tank is not in use.
Safety goggles or glasses must be worn when moving the tank.
Large tanks should not be carried, they should be secured to an approved cart.
All of the above are correct.
Aluminum ladders are safe to use around electrical equipment as long as they have insulation pads on the bottom of the rungs.
True
False
As long as the torch is kept moving below the level of the liquid refrigerant in the cylinder so as not to create a hotspot, it is OK to heat the cylinder in this manner.
True
False
When it is necessary to perform electrical work in an area that has a damp or wet floor, which of the following can be done to minimize the chance of electrical shock?
Place a rubber mat on the floor.
Use a wooden ladder.
Wear insulated boots and gloves.
All of the above
Refrigerants from a refrigeration system that has a burned out motor-compressor assembly can be dangerous because it could contain a high concentration of ____________________.
acid
toxins
oil
rust
When transferring refrigerants from a cylinder to a refrigeration system or any other container, you should always wear ____.
goggles with side shields and gloves
heavy protective clothing
rubber gloves
industrial steel-toed shoes and an insulated cap
It is possible that your hand would suffer frostbite if it comes in contact with liquid R-22 when accidentally releasing refrigerant into the atmosphere (an illegal procedure).
True
False
In electrical circuits, the _____ wire protects the operator.
live
control
grounding
neutral
Fires that involve ordinary materials such as paper, cardboard, and wood are classified as Type __________ fires.
A
B
C
D
An example of a pressure vessel is ____.
a small ship containing refrigerant cylinders
the compressor in a refrigeration unit
a cylinder containing refrigerant
a portable dolly
A necessary safety practice for a technician is to lockout the panel with a padlock and keep the key with you.
True
False
A fusible plug is a metal fitting that has a hole drilled through it and the hole is filled with ____.
material with a low melting point
plastic
copper fused with brass
a metal alloy that will burn when overheated
An R-22 cylinder containing enough refrigerant to have liquid refrigerant in it, is in a truck with a temperature of 120°F. What would be the psig pressure in the cylinder?
255.7 psig
259.9 psig
267.0 psig
271.5 psig
Fires that involve electrical equipment are classified as Type _____ fires.
A
B
C
D
A way to move equipment across a roof is to use rollers and ____________________ for a base.
plywood
carbon fiber
glass
If you are a refrigeration technician, a warm coat and gloves should be in your truck, even in the middle of the summer.
True
False
Fires that involve ordinary materials such as oil and gas are classified as Type __________ fires.
A
B
C
D
A double insulated drill ____.
has two ground wires to insure proper grounding
generally has a plastic case with the electrical connections and motor insulated within the tool
is used with a three- to two-prong adapter
has rechargeable batteries
To insure proper operation of an oxygen cylinder regulator, make sure no oil residue is present.
True
False
There are ____________________ microns in 1 mm Hg.
1,000
10,000
100,000
Noncondensable gases ____.
are desirable in a refrigeration system
are undesirable in a refrigeration system
condense readily under normal atmospheric conditions
help in pulling a vacuum
A micron gauge is used to measure ____.
atmospheric pressures at high altitudes
atmospheric pressures at sea level
absolute pressures below 1 mm Hg
high pressure in a refrigeration system
Sludge is produced when moisture, acid, and ____________________ are present in the system.
water
oil
acid
The oil in a vacuum pump should be changed after each time it is used.
True
False
To pull a vacuum means to ____.
raise the pressure in a refrigeration system
lower the pressure in a refrigeration system below atmospheric
allow refrigerant to escape into the atmosphere
condense the gas in the system
The maximum recommended pressure for leak testing is 150 psig on the low-pressure side of the system.
True
False
While under a deep vacuum, any liquid water under the oil in the motor-compressor assembly can be removed by operating the compressor motor for several seconds without any adverse effect on the system.
True
False
A multiple evacuation means that ____.
you connect three vacuum pumps simultaneously to a refrigeration system and pull a vacuum
you pull a vacuum on three different systems at the same time
you pull a vacuum on a refrigeration system more than once, allowing refrigerant or nitrogen into the system between each procedure
there must be more than one system operating before a vacuum can be pulled
A compound gauge ____.
indicates pressures above 14.696 psia
indicates pressures in inches Hg below atmospheric pressure
is one of two gauges on a typical gauge manifold
All of the above.
Which of the following represents the lowest vacuum?
10 psia.
5 in. Hg vacuum.
5 psig.
1000 microns.
To insure accurate testing, the best material to use for connecting lines to the vacuum pump and gauge set is ____.
light flexible hose
heavy duty rubber gauge line
copper tube
garden hose
When moisture is present in a refrigeration system, it will react with the refrigerant and the oil to form ____.
Carbon dioxide
acid
carbon monoxide
carbolic acid
A deep vacuum involves reducing the pressure in a refrigeration system to a micron gauge reading of ____________________ or below.
500
5,000
50,000
25,000
After repairing a system that has had an electrical motor failure (compressor burnout), it is good field practice to re-use the recovered refrigerant in that system.
True
False
A(n) ____________________ pressure could also mean refrigerant vapor is still seeping from the refrigeration system.
rising
dropping
stable
When using a "standing pressure test" for leak-checking, ____________________ should never be used since an explosive mixture can be created.
air
water
bubbles
The best method of leak checking is when the refrigeration system is ____.
in a vacuum
open to the atmosphere
operating with all fans activated
standing with dry nitrogen pressure of 150 psig in the system
Clearance tolerances are such that the ordinary clean refrigerant oil can be used satisfactorily in a vacuum pump.
True
False
At what pressure range does the technician valve off the vacuum pump when evacuating to a deep vacuum?
200 to 100 microns.
300 to 100 microns.
300 to 200 microns.
500 to 300 microns.
Air entering a refrigerant system can eventually lead to compressor failure.
True
False
Only two substances should be in the refrigeration system for proper operation. They are ____________________ and oil.
refrigerant
nitrogen
oxygen
Micron gauge displays can be electronic analog, digital, or ____________________.
light-emitting diode (LED)
Infrared
ultraviolet
Moisture in a liquid state must be ____ before it can be removed with a vacuum pump.
vaporized
condensed
cooled
solidified
The electronic vacuum gage is attached to the system so it can measure the pressure ____________________ the system.
inside
outside
When charging a refrigeration system with a near-azeotropic mixture, what must be done to prevent liquid from entering the system?
Charge only as a vapor through the high side.
Charge only liquid through the high side.
Charge as a liquid through the low side using a restrictor.
Charge as a vapor through the low side using a resistor.
When adding refrigerant in vapor form to an operating refrigeration system, the refrigerant must be added to the low-pressure side of the system.
True
False
When charging liquid refrigerant from a single valve supply cylinder, the cylinder is placed ____.
upside down
right side up
on its side
in any position indicated
When adding refrigerant in liquid form into the high-side of the system, the system motor/compressor assembly is running.
True
False
If 22 oz. of refrigerant are to be added to a refrigeration system and the supply cylinder weighs 24 lb. 12 oz. before any is added, what will be the supply cylinder weight after the system has been charged?
23 lb 12 oz.
22 lb 12 oz.
22 lb 6 oz.
23 lb 6 oz.
The quickest method to charge a system is to charge only vapor.
True
False
Refrigerant in vapor form is added to an operating system through the ____________________ side of the system.
low-pressure
high-pressure
When the warm refrigerant cylinder is connected to an operating system, the pressure in the cylinder will be ____________________ than the suction pressure of the system.
none of the below
higher
lower
the same as
Glide is the range of temperatures/pressures in which a blended refrigerant will condense.
True
False
Fractionation occurs when ____.
some of a blended refrigerant evaporates or condenses before the rest of the blend
when only a fraction of the total charge has been added to a system
the operating pressures of a system increase
Both a and c.
One good feature of an electronic charging scale is that it counts upward as refrigerant is removed, to tell the technician how much refrigerant was used.
True
False
As refrigerant vapor is removed from a supply cylinder, the pressure in the supply cylinder will ____________________.
fall
rise
remain constant
A graduated cylinder charging device is a device that ____.
measures refrigerant by volume for precise refrigerant charging
has a compensation dial for adjusting for the temperature of the refrigerant
often has a heater to keep the refrigerant temperature from dropping when refrigerant is released into the system
All of the above.
Charging a refrigeration system refers to ____.
removing refrigerant from a system
adding refrigerant to a system
cleaning the refrigerant
vaporizing the refrigerant
When charging a system with vapor refrigerant from a refrigerant cylinder, the cylinder will become ____.
cold
very warm
the same temperature as the ambient air
very cold
When the system pressures are lower than the pressure in the refrigerant tank, such as when the system has just been evacuated or if the system is out of refrigerant, refrigerant can be added to both the high and low pressure sides of the system.
True
False
If 30 oz. of refrigerant are to be added to a refrigeration system and the supply cylinder weighs 26 lb. 4 oz. before any is added, what will the supply cylinder weigh after the system has been charged?
22 lb 8 oz.
24 lb 6 oz.
24 lb 8 oz.
22 lb 4 oz.
If the tank is a reusable tank, there are no check valves and system refrigerant can enter the tank as long as the system pressure is higher than the pressure in the tank.
True
False
Refrigerant in liquid form is normally put into the system through the ____.
liquid line
suction line
hot gas line
liquid return line
Refrigerant in vapor form is normally put into the system through the ____.
liquid line
suction line
hot gas line
liquid return line
The ____________________ is used to help technicians perform a number of tasks including taking pressure readings on the high side of the system and trapping all of the system refrigerants in the receiver to perform system service.
king valve
TXV
Front seat
The charging device that holds refrigerant, has a visible column of liquid, and can be used to "visually" see the amount of refrigerant used is called the ____________________.
graduated cylinder
flask
If a critically charged refrigeration system is over charged, which of the following is a likely result?
Increased cooling capacity
Reduced compressor discharge temperature.
Increased system efficiency.
Increased operating pressures.
A manufacturer's charging chart may be used when available to determine the correct charge for a system.
True
False
The factory charge in a split system, using R-22, shows 6 lb. 8 oz. in the outdoor condensing unit and 2 oz. in the evaporator. The 3/8" liquid line contains 0.48 oz. per foot and the 7/8" suction line contains 0.10 oz. per foot. The refrigerant lines are 30' long. What is the correct refrigerant charge for this system?
6 lb 10 oz.
6 lb 15 oz.
7 lb 7 oz.
7 lb 11 oz.
Using a restrictor, liquid refrigerant can be charged into the low-side of the system with the system operating.
True
False
