WorksheetsFE in ME303P2
Total questions: 115
Worksheet time: 58mins
Name
Class
Date
1.
Which of the following could be used to check a leak in an ammonia system?
a)
A. Litmus paper
b)
B. Halide torch
c)
C. Sulfur stick
d)
A and C
2.
Ammonia leaks in the condenser can be detected by:
a)
smelling the discharge water
b)
applying litmus paper to the circulating water discharge
c)
adding oil of peppermint to the system and tracing and looking for bubbles
d)
applying a soapy solution to the condenser heads and looking for bubbles
3.
A sulfur stick burning in the presence of ammonia will give off a _____.
a)
dense yellow smoke
b)
dense yellow smoke
c)
dense white smoke
d)
dense green smoke
4.
An ammonia leak will turn litmus paper _____.
a)
blue
b)
green
c)
red
d)
yellow
5.
In an ammonia system the oil gauge must be kept:
a)
closed except when checking oil level
b)
open at all times
c)
close when machine is shut down
d)
open when machine is shut down
6.
Valves and piping in an ammonia system are made of:
a)
brass
b)
bronze
c)
iron
d)
copper
7.
The relief valve on an ammonia machine is located:
a)
A. on the discharge pipe from the condenser
b)
B. on the discharge pipe from the compressor
c)
C. in the compressor head
d)
A and B
8.
When purging an ammonia condenser into a bucket of water, one can tell when the air is out and ammonia starts to come through by the:
a)
smell of the ammonia being liberated from the water
b)
color of the water turning green
c)
color of the water turning bluish
d)
change of bubbling sound of air to the crackling sound of ammonia
9.
The crossover connection in an ammonia system can be used to _____.
a)
hot-gas defrost
b)
pump air out of the system
c)
add refrigerant to the system
d)
reduce the pressure on the discharge side of the condenser
10.
How is an ammonia system purged so that operator will not be overcome by the fumes?
a)
into a bucket of lube oil
b)
back into the compressor
c)
into a bucket of water
d)
into the atmospheric line
11.
Thermal expansion valves are usually of the:
a)
A. diaphragm
b)
B. magnetic type
c)
C. bellows type
d)
A and C
12.
When the evaporator coils are located in the icebox, the system is known as:
a)
indirect system
b)
direct system
c)
high-pressure system
d)
low-pressure system
13.
The purge valve is located:
a)
on the receiver discharge
b)
in the highest part of the system
c)
in the lowest part of the system
d)
on the evaporators coils
14.
The solenoid valve is:
a)
a pressure-controlled stop valve
b)
a temperature-controlled stop valve
c)
a Freon-controlled check valve
d)
none of these
15.
The thermal expansion valve is located between the:
a)
solenoid valve and the evaporator coils
b)
charging valve and the solenoid valve
c)
receiver and the king valve
d)
king valve and the solenoid valve
16.
The purpose of the scale trap is to:
a)
dissolved scale and dirt in the system
b)
remove insoluble gases from the refrigerant
c)
remove dirt, scale and metal chips from the refrigerant
d)
control the amount of scale going to the compressor
17.
The oil separator (trap) is located between the:
a)
compressor discharge valve and the condenser
b)
receiver and the expansion valve
c)
receiver and the king valve
d)
condenser and the receiver
18.
The charging connection in a refrigerating system is located:
a)
before the receiver
b)
between the condenser and the receiver
c)
between the receiver and the king valve
d)
between the king valve and the solenoid valve
19.
The dehydrator is located:
a)
condenser and receiver
b)
receiver and the expansion valve
c)
condenser and the king valve
d)
receiver and the king valve
20.
The charging valve is located between the:
a)
king valve and the expansion valve
b)
evaporator coils and the compressor
c)
compressor and the receiver
d)
receiver and the condenser
21.
The solenoid valve is located between the _____.
a)
thermal expansion valve and the evaporator
b)
scale trap and the thermal expansion valve
c)
king valve and the scale trap
d)
automatic and manual expansion valves
22.
A device used to keep moisture from passing through the system is called:
a)
humidifier
b)
dehydrator
c)
aerator
d)
trap
23.
The relief valve is located on the:
a)
discharge side on the condenser
b)
outlet of the evaporator coils
c)
receiver tank
d)
discharge side of the compressor
24.
The dehydrator is used:
a)
A. to remove moisture from the system
b)
B. when adding refrigerant to the system
c)
C. to remove air from the system
d)
A and B
25.
Which of the following is another name for the liquid valve?
a)
Freon valve
b)
king valve
c)
shutoff valve
d)
master valve
26.
If no gaskets are used in the piping joints of a Freon system, the:
a)
wielded joints
b)
finished joints
c)
ground joints
d)
soldered joints
27.
A device for holding open the suction valve and drawing gas from the suction manifold and returning it to the suction line without compressing is called _____.
a)
relief valve
b)
suction by-pass
c)
cylinder unloader
d)
discharge line by-pass
28.
The solenoid valve can be typed as a _____.
a)
bellow valve
b)
bimetallic valve
c)
thermal valve
d)
magnetic stop valve
29.
The bulb for the thermal expansion valve is located:
a)
near the evaporator coil outlet
b)
in the middle of evaporator coils
c)
near the evaporator coil inlet
d)
on the bottom row of evaporator coils
30.
The elements of a thermostat switch are usually of the _____.
a)
pilot-valve type
b)
bimetal type
c)
diaphragm type
d)
valve type
31.
The expansion valve is located between the:
a)
compressor and condenser
b)
evaporator and compressor
c)
receiver and evaporator
d)
condenser and receiver
32.
The oil separator is located between the:
a)
condenser and dehydrator
b)
compressor and condenser
c)
evaporator and compressor
d)
solenoid valve and thermal expansion valve
33.
A double-trunk piston is used to:
a)
prevent oil from mixing with the refrigerant
b)
absorb some of the side thrust
c)
prevent gas from getting to crankcase
d)
all of these
34.
Which of the following gasket materials should be used on a Freon system?
a)
A. Asbestos
b)
B. Metallic
c)
C. Rubber
d)
A and B
35.
Many pressure gauges on a Freon system have two dials or graduations on one gauge. The two dials represent:
a)
suction and discharge pressure
b)
pressure and temperature
c)
liquid and gas pressure
d)
cooling water inlet and outlet temperatures
36.
A double-pipe condenser has _____.
a)
two pipes for cooling water and one for refrigerant
b)
a small pipe inside a larger pipe, the cooling water passing through the small pipe and the refrigerant through the large pipe
c)
two piping system side by side, one with cooling water and one with refrigerant
d)
none of these
37.
When there is a Freon leak, the torch will burn:
a)
orange
b)
green
c)
blue
d)
white
38.
Large leaks in a Freon system cannot always be detected with a halide torch because it changes color with the slightest amount of Freon present. A large leak can be detected easier by applying _____.
a)
sheets of litmus paper to all joints and watch for color change
b)
a soapsuds solution, mixed with a little glycerin to hold the solution together, and watch for bubbles
c)
a thin layer of mineral oil to all joints and watch for bubbles
d)
a lighted candle at the joints and watch for leaky spots blowing candle
39.
The relief valve on a CO<sub>2</sub> Machine is located:
a)
next to the king valve
b)
in the compressor head
c)
on the discharge pipe between the compressor and the discharge valve
d)
on the discharge pipe from the condenser
40.
The discharge pressure of the compressor should be:
a)
the pressure which corresponds to a temperature from 5°F below that of the condenser discharge
b)
the pressure which corresponds to a temperature equal to that of the condenser discharge
c)
the pressure which corresponds to a temperature from 5°F to 15°F higher than the condenser discharge
d)
none of these
41.
The purpose of relief valves on refrigeration machines is to:
a)
A. by-pass the compressor when dehydrating
b)
B. prevent overloading in the iceboxes
c)
C. prevent excessive pressure in case of stoppage on the discharge side of the system
d)
A and B
42.
A leaky suction valve can usually be detected by:
a)
a higher suction pressure
b)
a fluctuating suction pressure gauge
c)
closing in on the suction valve having no effect on the suction pressure
d)
any of these
43.
Too low suction pressure could be caused by:
a)
too much oil in the system
b)
shortage of refrigerant gas
c)
dirty scale traps
d)
any of these
44.
What do you call a system in which the evaporator coils are located in a brine solution and the brine is pumped through the inbox?
a)
an indirect system
b)
a double-evaporator system
c)
a direct system
d)
a low-pressure system
45.
Before securing a compressor to do maintenance work on it, be sure to:
a)
A. purge the system
b)
B. have spare parts ready
c)
C. pump down the system
d)
B and C
46.
Obstruction of the valve is usually caused by:
a)
scale
b)
congealed oil the system
c)
water in the system
d)
any of the answer
47.
Excess frost on the evaporator coils:
a)
does not affect the system
b)
takes load off compressor
c)
reduces efficiency of the plant
d)
keeps the icebox cooler
48.
Air circulation in the icebox is accomplished by the use of which of the following?
a)
hollow sidewalls
b)
diffuser fans
c)
louver doors
d)
air vents to deck
49.
The cooling-water side of the condenser should be opened for inspection every:
a)
six months
b)
two years
c)
year
d)
three months
50.
Some causes of a noisy compressor are:
a)
worn bearing, pins, etc.
b)
slugging due to flooding back of refrigerant
c)
too much oil on crankcase
d)
any of these
51.
If the thermal expansion valve becomes inoperative, the iceboxes will have to be controlled the _____.
a)
king valve
b)
manual expansion valve
c)
manual solenoid valve
d)
solenoid valve
52.
Sweating of the crankcase is caused by which of the following?
a)
too much oil in the system
b)
insufficient superheat
c)
too much superheat
d)
expansion valve hung up
53.
Which of the following is the usual cause of slugging?
a)
too much refrigerant in the system
b)
too much oil in the system
c)
expansion valve not operating properly
d)
too much cooling water to condenser
54.
What operates low-pressure cutout switch?
a)
bellows
b)
spring tension
c)
a magnet
d)
water pressure
55.
Which of the following must be checked up if an automatic Freon system will not start up?
a)
high-pressure cutout
b)
reset mechanism
c)
low-pressure cutout
d)
all of these
56.
Which of the following is the probable cause of hot suction line?
a)
insufficient lubrication
b)
too much refrigerant
c)
insufficient refrigerant
d)
expansion valve closed too much
57.
What do you call the device that is used as a low-pressure control and high-pressure cutout on a compressor?
a)
pressure controller
b)
controller switch
c)
cutout
d)
cutout switch
58.
If the solenoid valve closed by accident, the compressor would be stopped by which of the following?
a)
automatic trip
b)
low-pressure cutout switch
c)
low-water cutout switch
d)
high-pressure cutout switch
59.
The purpose of the low-pressure cutout switch is to:
a)
cutout the compressor at a set pressure
b)
maintain a preset suction pressure to the compressor
c)
maintain liquid refrigerant at the suction of the compressor
d)
cut compressor in and out at a preset pressure
60.
If the cooling water to the condenser suddenly fails?
a)
an alarm will ring to notify the engineer
b)
the compressor will shut down
c)
the expansion valve will close
d)
the solenoid valve will close
61.
The most likely cause of high superheat would be:
a)
too much refrigerant
b)
expansion valve open too wide
c)
expansion valve closed too much
d)
back-pressure valve set too high
62.
What do you call the liquid researching the compressor through the suction?
a)
superheating
b)
overflowing
c)
flooding back
d)
recycling
63.
The suction pressure switch is operated by which of the following?
a)
electronic current
b)
pressure on a bellows
c)
a relay cutout
d)
thermocouple
64.
If the compressor short-cycles on the high-pressure cutout, which of the following would you check?
a)
a check for too much refrigerant in the system
b)
if plenty of cooling water is running through but it is not picking up heat, the condenser tubes need cleaning
c)
be sure system is getting cooling water
d)
all of these
65.
A Freon unit will tend to short-cycle when operating under:
a)
normal conditions
b)
heavy loads
c)
light loads
d)
all of these
66.
Air is remove from the system by:
a)
opening the purge valve
b)
increasing the amount of cooling water
c)
running the refrigerant through an aerator
d)
running the refrigerant through a deaerator
67.
Short-cycling means that the machine:
a)
runs to slow
b)
stops and starts frequently
c)
runs too fast
d)
grounds out frequently
68.
The suction pressure in a Freon system should be:
a)
the pressure which corresponds with a temperature about 20o F above the temperature of the icebox
b)
the pressure corresponds with a temperature about 200 F below the temperature of the icebox
c)
the pressure which corresponds with a temperature equal to the temperature of the icebox
d)
none of these
69.
If any of the electrically controlled devices in a Freon system malfunction, which of the following valve will also automatically shut off?
a)
king valve
b)
Condenser cooling-water inlet valve
c)
Expansion valve
d)
Solenoid valve
70.
A leaky discharge valve can usually be detected by:
a)
a drop in icebox temperature
b)
a discharge pressure lower than normal
c)
a fluctuating high-pressure gauge
d)
any of these
71.
The dehydrating agent in a Freon system is usually:
a)
sodium chloride
b)
calcium chloride
c)
activated alumina
d)
slaked lime
72.
If the compressor short-cycles on the low-pressure cutout, the trouble might be:
a)
too much frost on the evaporator coils
b)
dirty traps and strainers
c)
lack of refrigerant
d)
any of these
73.
If an electrically operated compressor failed to start, the cause might be:
a)
a blown fuse
b)
burned out holding coils in solenoid valve
c)
an open switch
d)
any of these
74.
The high-pressure side of the system is sometimes referred to as the:
a)
hot side
b)
suction side
c)
cold side
d)
cooling side
75.
If the compressor were to run continuously without lowering the temperature, the trouble would probably be:
a)
leaky discharge valves
b)
insufficient refrigerant in the system
c)
leaks in the system
d)
any of these
76.
If frost forms on the cylinders, the cause would be:
a)
charging valve left open
b)
expansion valve not open wide enough
c)
expansion valve open too wide
d)
dehydrator not working properly
77.
Which of the following would cause low head pressure?
a)
A. insufficient cooling water
b)
B. too much cooling water
c)
C. insufficient refrigerant gas
d)
B and C
78.
Too high suction pressure could be cause by:
a)
leaky suction valves
b)
expansion valve bulb not working properly
c)
expansion value open too wide
d)
any of these
79.
Which of the following would cause high head pressure?
a)
air in the condenser
b)
insufficient cooling water
c)
dirty condenser
d)
any of these
80.
Which of the following would cause a high suction pressure?
a)
expansion valve open too wide
b)
dirty dehydrator
c)
king valve not open wide enough
d)
expansion valve not open wide enough
81.
If a compressor runs continuously, the cause might be a:
a)
clogged scale trap
b)
defective thermal bulb
c)
stuck high-pressure switch
d)
stuck low-pressure switch
82.
Low suction pressure is caused by:
a)
expansion valve causing flooding back
b)
solenoid valve not functioning properly
c)
leaky compressor suction valves
d)
air in the system
83.
How is a Freon system purged?
a)
with a reefer pump
b)
the same as an ammonia system
c)
back to the extra supply tank
d)
the same as a CO<sub>2</sub> system
84.
If the compressor discharge temperature is higher than the receiver temperature:
a)
add more refrigerant to the system
b)
decrease the amount of cooling water to the condenser
c)
increase the amount of cooling water to the condenser
d)
remove some of the refrigerant from the system
85.
How is a CO<sub>2</sub> system purged?
a)
when is a CO<sub>2</sub> comes out of the purge valve, frost will from on a piece of metal held near the outlet
b)
through the king valve
c)
pumped out with a suction pump
d)
the CO<sub>2</sub> will come of the purge valve in liquid form
86.
The system should be purged:
a)
while starting up
b)
after the system has been shut down for a few hours
c)
while system is operating
d)
once a week
87.
If the compressor had been running satisfactorily for a long period of time but suddenly the compartment temperature started to rise, the trouble must be:
a)
a refrigerant leak has developed
b)
the expansion valve may contain frozen water
c)
the solenoid valve has jammed shut
d)
any of these
88.
If the compressor had been running satisfactorily for a long period of time but the oil level was rising slowly, one should:
a)
check the dehydrator cartridge
b)
check to see if there is too much refrigerant in the system
c)
shut down the compressor and check the oil level with the machine stopped
d)
drain out sufficient oil to bring it down to the proper running level
89.
The purpose of the trap is:
a)
to add oil to the compressor
b)
to remove oil from the refrigerating gas
c)
to remove oil from the charging tank
d)
none of these
90.
Too much oil in the compressor would:
a)
absorb too much refrigerant from the system
b)
deposit oil on the condenser tubes
c)
damage the expansion valve
d)
caused leakage through the shaft seals
91.
The oil level in the compressor should be checked:
a)
just before starting the compressor
b)
after a long period of operation
c)
after an extended lay-up period
d)
while the compressor is in operation
92.
Which of the following would not cause high suction pressure?
a)
suction valve not adjusted properly
b)
expansion valve stuck open
c)
leaky suction valve
d)
insufficient refrigeration
93.
Water in the refrigerant is liable to:
a)
freeze on the expansion valve seat and cut the flow of refrigerant
b)
clog the oil trap
c)
freeze in the king (liquid) valve
d)
emulsify the oil In the compressor
94.
The function of the expansion valve is to:
a)
regulate the amount of liquid refrigerant to the expansion coils
b)
change the gas refrigerant to a liquid
c)
shut off the flow of refrigerant to the condenser
d)
change the high-pressure liquid to a low-pressure liquid
95.
When charging Freon system, all the valves should be in their normal position except the:
a)
solenoid valve
b)
purge valve
c)
king (liquid) valve
d)
expansion valve
96.
The purpose of the receiver is to:
a)
cool the refrigerant gas
b)
separate the oil from the refrigerant
c)
store the refrigerant
d)
condense the refrigerant
97.
The solenoid valve controls the:
a)
amount of refrigerant entering the evaporator coils
b)
amount of refrigerant going to the compressor
c)
amount of the refrigerant going to the evaporator
d)
pressure if the refrigerant going to the evaporator coils
98.
The purpose of the evaporator is to:
a)
absorb latent heat of vaporization
b)
absorb latent heat of fusion
c)
transfer latent heat of vaporization
d)
transfer latent heat of fusion
99.
The purpose of the dehydrator is to:
a)
add more refrigerant to the system
b)
remove oil from the refrigerant
c)
remove moisture from the crankcase oil
d)
remove moisture from the refrigerant
100.
The principle of mechanical refrigerant is:
a)
the conversion of a liquid to a gas
b)
the absorption of temperature under heat, pressure, compression and expansion
c)
the compression of a liquid under temperature and expansion
d)
the absorption of heat under temperature, compression pressure and expansion
101.
A thermostat is a:
a)
temperature-operated switch
b)
pressure-operated switch
c)
superheat-operated switch
d)
back-pressure-operated switch
102.
The thermal expansion valve responds to the:
a)
amount of superheat in the vapor
b)
amount of superheat in the liquid
c)
temperature in the evaporator coils
d)
pressure in the evaporator coils
103.
The expansion valve on a Freon system controls the:
a)
superheat of the gas leaving the compressor
b)
back pressure in the evaporator
c)
temperature of the box
d)
superheat of the leaving the evaporator
104.
The purpose of the expansion valve by-pass is to:
a)
increase the efficiency of the plant
b)
increase the capacity of the evaporator
c)
control the refrigerant to the evaporator in case the automatic valves fail
d)
bypass the compressor
105.
The thermal expansion valve:
a)
controls the amount of gas coming from the dehydrator
b)
controls the quantity of liquid refrigerant going to the evaporator coils
c)
controls the amount of gas going to the receiver
d)
removes trapped oil from the refrigerant
106.
The function of the compressor is to:
a)
pull the refrigerant gas through the system
b)
increase the pressure of the refrigerant
c)
discharge the refrigerant to the condenser
d)
all of these
107.
The solenoid valve is controlled by:
a)
the amount of liquid in the system
b)
the amount of gas in the system
c)
the temperature in the condenser
d)
the temperature in the icebox
108.
Oil is added to a Freon compressor by:
a)
shutting down the machine and pouring in through the crankcase inspection plate opening
b)
pumping in with an electric-driven pump
c)
pumping in with a hand pump
d)
pouring through oil hole in base
109.
When adding oil to a Freon system, one must be sure that:
a)
the condenser is shut down
b)
all air is removed from the pump and fitting
c)
there is not too high a suction pressure
d)
the discharge pressure is not too high
110.
To help a person who had been overexposed to ammonia gas, one would:
a)
apply cold compresses
b)
apply artificial respiration
c)
douse with cold water
d)
wrap in warm blankets
111.
Ammonia will corrode:
a)
brass
b)
copper
c)
bronze
d)
all of these
112.
A refrigerating unit of one (1) ton capacity can remove:
a)
100 Btu’s per min.
b)
288 Btu’s per min.
c)
200 Btu’s per min.
d)
500 Btu’s per min.
113.
The refrigerant with the lowest boiling point is:
a)
NH<sub>2</sub>
b)
F12
c)
CO<sub>2</sub>
d)
F22
114.
A ton of refrigeration is equal to the removal of:
a)
288,000 Btu per 24 hrs.
b)
28,000 Btu per 24 hrs.
c)
28,000 Btu per 24 hrs.
d)
280,000 Btu per 24 hrs.
115.
The boiling point of Freon-12 at atmospheric pressure is:
a)
+22°F
b)
-22°F
c)
+22°C
d)
-22°C
100 %
