Unlock document.
This document is partially blurred.
Unlock all pages and 1 million more documents.
Get Access
154)
154)
An R-22 refrigeration system requires a superheat of 8°F. If the evaporator saturation pressure is
43 psig, what should the bulb temperature be?
A)
35°F
B)
8°F
C)
28°F
D)
51°F
Answer:
C
Explanation:
A)
B)
C)
D)
155)
155)
What are the parts of a distributor?
A)
A nozzle, handle, and piston with only one hole in the nozzle
B)
A nozzle, conical divider, and multiple holes around the divider cone
C)
A nozzle with multiple holes only
D)
A conical divider with multiple holes only
Answer:
B
Explanation:
A)
B)
C)
D)
156)
156)
A TEV with a dead power element will operate:
A)
With a higher-than-normal evaporator pressure.
B)
Correctly until an adjustment is made to the valve.
C)
With a high superheat.
D)
With a low superheat.
Answer:
C
Explanation:
A)
B)
C)
D)
157)
157)
Valves that use motors that move in tiny increments are:
A)
Pulse-modulated valves.
B)
Step motor valves.
C)
Cross-charged expansion valves.
D)
Electronic expansion valves.
Answer:
B
Explanation:
A)
B)
C)
D)
41
158)
158)
As refrigerant passes through the metering device, it:
A)
Drops in pressure and temperature.
B)
Drops in temperature but not in pressure.
C)
Increases in pressure and temperature.
D)
Drops in pressure, but not in temperature.
Answer:
A
Explanation:
A)
B)
C)
D)
159)
159)
Two types of fixed metering devices are:
A)
Capillary tubes and orifices.
B)
High-pressure and low-pressure.
C)
Pressure-reducing and pressure-increasing.
D)
Copper and brass.
Answer:
A
Explanation:
A)
B)
C)
D)
160)
160)
What two pieces of information are necessary to measure the TEV superheat?
A)
The valve body temperature and the bulb temperature
B)
The suction line temperature and pressure
C)
The liquid line and suction line temperatures
D)
The evaporator inlet and outlet temperatures
Answer:
B
Explanation:
A)
B)
C)
D)
161)
161)
Refrigerant leaves the metering device:
A)
As a subcooled liquid.
B)
As a saturated mixture of liquid and vapor.
C)
In the same physical state that it entered.
D)
As a superheated gas.
Answer:
B
Explanation:
A)
B)
C)
D)
42
162)
162)
Latent cooling:
A)
Removes water from the air.
B)
Is an interesting theory that has not been proven.
C)
Reduces the air temperature.
D)
Reduces the air temperature and removes water.
Answer:
A
Explanation:
A)
B)
C)
D)
163)
163)
Flooded evaporators are used in:
A)
Large chillers.
B)
Ice cream freezers.
C)
Residential air conditioners.
D)
Window air-conditioning units.
Answer:
A
Explanation:
A)
B)
C)
D)
164)
164)
Medium-temperature applications are usually between:
A)
28°F to 40°F.
B)
26°F to 43°F.
C)
20°F to 32°F.
D)
47°F to 60°F.
Answer:
A
Explanation:
A)
B)
C)
D)
165)
165)
What is the main purpose of the fins on tube-and-fin evaporators?
A)
Fins protect the coil from being punctured by projectiles.
B)
Fins direct the condensed water to the drain pan.
C)
Fins increase the surface area of the coil.
D)
Fins direct the air more smoothly across the coil.
Answer:
C
Explanation:
A)
B)
C)
D)
43
166)
166)
In a direct-expansion chiller:
A)
The water and refrigerant are mixed in the shell.
B)
The water is in the shell and the refrigerant is in the tubes.
C)
The water is in the tubes and the refrigerant is in the shell.
D)
The water and refrigerant are in separate tubes with a heat transfer medium in the shell.
Answer:
B
Explanation:
A)
B)
C)
D)
167)
167)
The refrigeration system component that absorbs heat out of the product is the:
A)
Expansion device.
B)
Condenser.
C)
Evaporator.
D)
Compressor.
Answer:
C
Explanation:
A)
B)
C)
D)
168)
168)
Increasing the airflow across a coil:
A)
Increases the latent capacity.
B)
Increases the sensible capacity.
C)
Decreases the static pressure drop across the coil.
D)
Decreases the bypass factor.
Answer:
B
Explanation:
A)
B)
C)
D)
169)
169)
Commercial refrigeration equipment for ice cream storage typically uses:
A)
High-temperature evaporators.
B)
Medium-temperature evaporators.
C)
Low-temperature evaporators.
D)
Ultra-low-temperature evaporators.
Answer:
C
Explanation:
A)
B)
C)
D)
44
170)
170)
As a mixture travels through an evaporator, the liquid percentage:
A)
Stays the same.
B)
Increases slightly.
C)
Increases greatly.
D)
Decreases.
Answer:
D
Explanation:
A)
B)
C)
D)
171)
171)
Sensible cooling:
A)
Is an interesting theory that has not been proven.
B)
Reduces the air temperature and removes water.
C)
Reduces the air temperature.
D)
Removes water from the air.
Answer:
C
Explanation:
A)
B)
C)
D)
172)
172)
Commercial refrigeration equipment for eggs, produce, and dairy uses:
A)
High-temperature evaporators.
B)
Medium-temperature evaporators.
C)
Low-temperature evaporators.
D)
Ultra-low-temperature evaporators.
Answer:
B
Explanation:
A)
B)
C)
D)
173)
173)
The most common types of defrost for commercial refrigeration evaporators are:
A)
Reverse cycle and air defrost.
B)
Electric and hot-gas defrost.
C)
Inductive and ultrasonic defrost.
D)
Mechanical and hydraulic.
Answer:
B
Explanation:
A)
B)
C)
D)
45
174)
174)
For which of the following actions is the last part of the evaporator used?
A)
Increasing the vapor percentage
B)
Lowering the liquid percentage
C)
Raising the liquid percentage
D)
Superheating the refrigerant
Answer:
D
Explanation:
A)
B)
C)
D)
175)
175)
How does an air-defrost system work?
A)
Hot compressor discharge gas is routed to the evaporator.
B)
A warm glycol solution is sprayed on the coil.
C)
The superheated gas leaving the evaporator is used to melt the ice.
D)
Air from inside the store is directed over the evaporator.
Answer:
D
Explanation:
A)
B)
C)
D)
176)
176)
When an evaporator coil gets dirty:
A)
The static pressure drop across the coil increases.
B)
The static pressure drop across the coil decreases.
C)
The temperature drop across the coil decreases.
D)
The thermostatic expansion valve feeds more refrigerant to compensate.
Answer:
C
Explanation:
A)
B)
C)
D)
177)
177)
Which of the following is considered an advantage of a flooded evaporator?
A)
Its ability to maintain a very accurate temperature across half of the evaporator surface
B)
Its ability to maintain a very accurate temperature across the entire evaporator surface
C)
Its ability to raise the temperature across the entire evaporator surface
D)
Its ability to lower the temperature across the entire evaporator surface
Answer:
B
Explanation:
A)
B)
C)
D)
46
178)
178)
Where are plate evaporators typically used?
A)
Large flooded chillers
B)
Direct expansion chillers
C)
Air-conditioning coils
D)
Small residential refrigerators
Answer:
D
Explanation:
A)
B)
C)
D)
179)
179)
Which of the following is NOT a high-temperature refrigeration application?
A)
Fresh flower storage
B)
Dry goods storage
C)
Fresh meat storage
D)
Candy storage
Answer:
C
Explanation:
A)
B)
C)
D)
180)
180)
The distance between fins is classified as the:
A)
Refrigerant tube.
B)
Heating space.
C)
Fin tube.
D)
Fin spacing.
Answer:
D
Explanation:
A)
B)
C)
D)
181)
181)
To increase latent cooling capacity:
A)
Raise the evaporator pressure.
B)
Reduce the airflow over the evaporator.
C)
Reverse the direction of airflow over the evaporator.
D)
Increase the airflow over the evaporator.
Answer:
B
Explanation:
A)
B)
C)
D)
47
182)
182)
Increasing the airflow across a coil:
A)
Increases the temperature drop across the coil.
B)
Increases the latent cooling capacity of the coil.
C)
Increases the static pressure drop across the coil.
D)
Decreases the static pressure drop across the coil.
Answer:
C
Explanation:
A)
B)
C)
D)
183)
183)
An evaporator that covers the coils being cooled with liquid refrigerant is a:
A)
Saturated evaporator.
B)
Direct expansion evaporator.
C)
Flooded evaporator.
D)
Carbureting evaporator.
Answer:
C
Explanation:
A)
B)
C)
D)
184)
184)
Water that condenses on an evaporator coil and is blown off by the velocity of the air through the
coil is called condensate:
A)
Blowoff.
B)
Blowdown.
C)
Make-up water.
D)
Bleedoff.
Answer:
A
Explanation:
A)
B)
C)
D)
185)
185)
Which of the following is the range of fin spacing on low-temperature coils?
A)
15 pins per inch
B)
69 pins per inch
C)
79 pins per inch
D)
14 pins per inch
Answer:
D
Explanation:
A)
B)
C)
D)
48
186)
186)
Air-conditioning tube-and-fin coils are commonly available as:
A)
Slab coils, slant coils, "A" coils, and "N" coils.
B)
"N" coils, "T" coils, and "P" coils.
C)
"A" coils, "T" coils, and "O" coils.
D)
Slant coils, "T" coils, and "P" coils.
Answer:
A
Explanation:
A)
B)
C)
D)
187)
187)
A compound is a combination of two or more chemicals:
A)
That form a mixture which can be separated through distillation.
B)
That form a homogeneous mixture.
C)
That form a mixture which cannot be separated by distillation.
D)
That form a completely new chemical with its own physical and chemical properties.
Answer:
D
Explanation:
A)
B)
C)
D)
188)
188)
Ozone is an oxygen molecule formed with:
A)
Chlorine to produce a new compound.
B)
Three oxygen atoms instead of the normal two.
C)
Two oxygen atoms instead of the normal three.
D)
Freon to produce a new compound.
Answer:
B
Explanation:
A)
B)
C)
D)
189)
189)
A refrigerant's temperature is controlled by its:
A)
Pressure.
B)
Molecular structure.
C)
Environment.
D)
State.
Answer:
A
Explanation:
A)
B)
C)
D)
49
190)
190)
The temperature where small bubbles first start to form in saturated liquid is known as the:
A)
Critical point.
B)
Dew point.
C)
Triple point.
D)
Bubble point.
Answer:
D
Explanation:
A)
B)
C)
D)
191)
191)
Which of the following refrigerant safety designations indicate the refrigerant is nonflammable?
A)
B3
B)
B1
C)
A3
D)
A2
Answer:
B
Explanation:
A)
B)
C)
D)
192)
192)
The refrigeration oil most commonly used with CFCs and HCFCs is:
A)
Mineral oil.
B)
Alkylbenzene.
C)
Polyol ester.
D)
Polyalkylene glycol.
Answer:
A
Explanation:
A)
B)
C)
D)
193)
193)
The temperature where small droplets of liquid first start to form in a saturated gas is known as
the:
A)
Critical point.
B)
Bubble point.
C)
Triple point.
D)
Dew point.
Answer:
D
Explanation:
A)
B)
C)
D)
50
194)
194)
A general definition of refrigerant is:
A)
A fluid that can turn heat into mass.
B)
The fluid used in a refrigeration system for transferring heat.
C)
A fluid that is naturally cold.
D)
A hydrocarbon-based chemical with noble elements replacing some of the hydrogen atoms.
Answer:
B
Explanation:
A)
B)
C)
D)
195)
195)
Refrigerants with the highest ozone depletion potential are:
A)
CFCs - chlorofluorocarbons.
B)
HFCs - hydrofluorocarbons.
C)
HCFCs - hydrochlorofluorocarbons.
D)
HCs - hydrocarbons.
Answer:
A
Explanation:
A)
B)
C)
D)
196)
196)
A fluorinated refrigerant whose number starts with a 1 is:
A)
A compound.
B)
Zeotropic.
C)
Azeotropic.
D)
Flammable.
Answer:
A
Explanation:
A)
B)
C)
D)
197)
197)
Examples of halogenated refrigerants include:
A)
CFCs, HCFCs, and HFCs.
B)
CFCs only.
C)
All refrigerants are halogenated.
D)
CFCs and HCFCs only.
Answer:
A
Explanation:
A)
B)
C)
D)
51
198)
198)
What difference is there between handling zeotropes and azeotropes?
A)
There is no difference in how zeotropes and azeotropes are handled.
B)
Azeotropes must leave the cylinder as a liquid but zeotropes may leave the cylinder as
either a liquid or a vapor.
C)
Zeotropes must leave the cylinder as a liquid but azeotropes may leave the cylinder as
either a liquid or a vapor.
D)
Zeotropes can be flammable and azeotropes are nonflammable.
Answer:
C
Explanation:
A)
B)
C)
D)
199)
199)
A refrigerant's safety rating is a combination of the toxicity letter and the:
A)
Pressure rating.
B)
Freezing point.
C)
Flammability number.
D)
Oxygen saturation.
Answer:
C
Explanation:
A)
B)
C)
D)
200)
200)
The pressure of a refrigerant cylinder containing saturated refrigerant:
A)
Is determined entirely by the temperature of the refrigerant.
B)
Is determined entirely by the amount of gas in the cylinder.
C)
Is determined by the amount of liquid in the cylinder.
D)
Is determined by both the amount of refrigerant in the cylinder and the cylinder
temperature.
Answer:
A
Explanation:
A)
B)
C)
D)
201)
201)
A fluorinated refrigerant whose number starts with a 4 is:
A)
A compound.
B)
Zeotropic.
C)
Azeotropic.
D)
Flammable.
Answer:
B
Explanation:
A)
B)
C)
D)
52
202)
202)
A fluorinated refrigerant whose number starts with a 5 is:
A)
A compound.
B)
Zeotropic.
C)
Azeotropic.
D)
Flammable.
Answer:
C
Explanation:
A)
B)
C)
D)
203)
203)
The refrigerant inside most refrigerant cylinders is a:
A)
Saturated liquid-vapor mix.
B)
Subcooled liquid.
C)
Homogeneous mixture of liquid and vapor.
D)
Superheated vapor.
Answer:
A
Explanation:
A)
B)
C)
D)
204)
204)
Refrigerants release heat:
A)
By converting refrigerant molecules into heat energy.
B)
By condensing from a vapor to a liquid.
C)
By evaporating from a liquid to a vapor.
D)
By rearranging their molecular structure to form a new compound.
Answer:
B
Explanation:
A)
B)
C)
D)
205)
205)
The pressure of a saturated refrigerant can accurately be predicted:
A)
Only if the amount of refrigerant in the system is known.
B)
By multiplying the ratio of liquid to vapor times the refrigerant's base saturation
temperature.
C)
By comparing its temperature to the corresponding pressure on a pressure-temperature
chart.
D)
By multiplying the refrigerant's molecular weight times the average molecular kinetic
speed.
Answer:
C
Explanation:
A)
B)
C)
D)
53
206)
206)
How are refrigerants with a higher toxicity level labeled?
A)
Letter "A"
B)
Letter "B"
C)
Letter "D"
D)
Letter "C"
Answer:
B
Explanation:
A)
B)
C)
D)
207)
207)
A refrigerant blend with a glide of 2°F or less would be considered:
A)
A low glide blend.
B)
A high glide blend.
C)
An azeotrope.
D)
A compound.
Answer:
A
Explanation:
A)
B)
C)
D)
208)
208)
Which of the following is a promising new refrigerant lubricant?
A)
Mineral oil
B)
Polyol ester
C)
Polyalkylene glycol
D)
Polyvinylether
Answer:
D
Explanation:
A)
B)
C)
D)
209)
209)
Which of the following refrigerant safety designations indicate the refrigerant would require more
than 400 parts per million to be hazardous?
A)
B3
B)
B1
C)
A1
D)
B2
Answer:
C
Explanation:
A)
B)
C)
D)
210)
210)
A flow control device that stops or allows the flow of a refrigerant in a refrigeration system based
on an electric signal in:
A)
An automatic expansion valve.
B)
An evaporator pressure regulator.
C)
A crankcase pressure regulator.
D)
A solenoid valve.
Answer:
D
Explanation:
A)
B)
C)
D)
54
211)
211)
Along with the refrigerant that is being discharged, compressors will discharge which of the
following as it leaves the compressor?
A)
Oil
B)
Vapor
C)
Water
D)
Carbon dioxide
Answer:
A
Explanation:
A)
B)
C)
D)
212)
212)
Why are liquid-line filter driers required for all systems using HFC refrigerant?
A)
Because HFC refrigerants often form fluoride crystals inside the system.
B)
Because the filter drier is also the metering device in newer systems.
C)
Because the POE oil used with HFC refrigerant is very hygroscopic.
D)
Because the filter drier also serves as a reservoir for refrigerant.
Answer:
C
Explanation:
A)
B)
C)
D)
213)
213)
In most commercial refrigeration systems, most of the excess refrigerant that is not being used is
stored in:
A)
The bottom of the evaporator.
B)
The liquid-line filter.
C)
The bottom of the condenser.
D)
The liquid receiver.
Answer:
D
Explanation:
A)
B)
C)
D)
214)
214)
One method of elevating system liquid pressure is to:
A)
Control the pressure of the condenser fan motors.
B)
Control the operation of the condenser fan motors.
C)
Control the temperature of the condenser fan motors.
D)
Control the vibration of the condenser fan motors.
Answer:
B
Explanation:
A)
B)
C)
D)
55
215)
215)
What is the material inside the filter drier called?
A)
Alcohol
B)
Wadding
C)
Desiccant
D)
Hydrogen peroxide
Answer:
C
Explanation:
A)
B)
C)
D)
216)
216)
Why is it necessary to have controls for maintaining a minimum high-side pressure on outdoor
air-cooled condensers?
A)
Refrigeration metering devices require a minimum pressure drop to operate.
B)
Compressors will not operate correctly if the compression ratio is too low.
C)
The refrigerant will not condense if it is excessively cooled.
D)
The chemical components in the refrigerant will separate if the pressure is allowed to drop
below the normal minimum operating pressure.
Answer:
A
Explanation:
A)
B)
C)
D)
217)
217)
A refrigeration component whose purpose is to prevent liquid refrigerant from returning to the
compressor is:
A)
A suction-line accumulator.
B)
A crankcase pressure regulator.
C)
A suction-line filter.
D)
A liquid receiver.
Answer:
A
Explanation:
A)
B)
C)
D)
218)
218)
Why is the filter drier important?
A)
It keeps the system clean and dry.
B)
It keeps the system quiet.
C)
It keeps the system running and oiled.
D)
It keeps the valves together.
Answer:
A
Explanation:
A)
B)
C)
D)
56
219)
219)
Moisture indicators are normally part of:
A)
A suction accumulator.
B)
A liquid receiver.
C)
A filter drier.
D)
A sightglass.
Answer:
D
Explanation:
A)
B)
C)
D)
220)
220)
What types of systems use evaporator pressure regulators (EPR)?
A)
Systems that require a constant evaporator pressure
B)
Systems with multiple compressors
C)
Systems with multiple evaporators
D)
Systems with multiple condensers
Answer:
C
Explanation:
A)
B)
C)
D)
221)
221)
Which of the following types of valve is NOT considered an isolation valve?
A)
Solenoid valve
B)
Ball valve
C)
Diaphragm valve
D)
Stem-type valve
Answer:
A
Explanation:
A)
B)
C)
D)
222)
222)
Which refrigeration device would most likely be installed in the discharge line leaving the
compressor to prevent liquid refrigerant from draining from a raised condenser into the
compressor head?
A)
A normally-open solenoid valve
B)
A crankcase pressure regulator
C)
A normally-closed solenoid valve
D)
A check valve
Answer:
D
Explanation:
A)
B)
C)
D)
57
223)
223)
A suction-to-liquid line heat exchanger:
A)
Decreases both superheat and subcooling.
B)
Decreases the superheat while increasing the subcooling.
C)
Increases both superheat and subcooling.
D)
Increases the superheat while decreasing the subcooling.
Answer:
C
Explanation:
A)
B)
C)
D)
224)
224)
What type of systems normally use crankcase pressure regulators?
A)
Any refrigeration system with a compressor that has a positive-pressure oil pump
B)
Commercial refrigeration applications with evaporator temperatures above 40°F
C)
Primarily comfort cooling applications
D)
Low-temperature refrigeration applications such as walk-in and reach-in freezers
Answer:
D
Explanation:
A)
B)
C)
D)
225)
225)
Which of the following conditions is NOT considered when selecting a CPR valve?
A)
Refrigerant
B)
Humidification capacity of the system
C)
Pressure drop across the valve at design load conditions
D)
Design suction pressure of the system
Answer:
B
Explanation:
A)
B)
C)
D)
58
226)
226)
What does an evaporator pressure regulator do?
A)
Evaporator pressure regulator is simply another name for thermostatic expansion valve.
B)
It is used in place of a more traditional refrigerant expansion device.
C)
It will not allow the evaporator pressure to rise above its setpoint, even if the suction
pressure is higher.
D)
It will not allow the evaporator pressure to drop below its setpoint, even if the suction
pressure is lower.
Answer:
D
Explanation:
A)
B)
C)
D)
227)
227)
The advantage of ball valves over other types of manual refrigeration valves is that they:
A)
Normally require special tools to open, preventing tampering by untrained personnel.
B)
Have venturi jets that help offset the pressure loss through the valve.
C)
Offer less resistance to flow.
D)
Have integral ports that allow pressure drop measurements.
Answer:
C
Explanation:
A)
B)
C)
D)
228)
228)
What is the advantage of using a pressure relief valve to protect a receiver instead of a fusible
plug?
A)
Pressure relief valves can also be used to check the receiver pressure.
B)
The pressure relief valve resets itself.
C)
Pressure relief valves are less expensive.
D)
It is impossible for a pressure relief valve to malfunction.
Answer:
B
Explanation:
A)
B)
C)
D)
59
229)
229)
How can a technician determine when a filter drier is stopped up and needs changing?
A)
The clogged filter flag will pop out.
B)
The indicating chemical disc will change color.
C)
The drier will vibrate violently.
D)
The pressure drop will exceed 2 psig.
Answer:
D
Explanation:
A)
B)
C)
D)
230)
230)
The specific enthalpy lines:
A)
Run diagonally from left to right.
B)
Run vertically from top to bottom.
C)
Run diagonally from right to left.
D)
Run horizontally from the left to the right.
Answer:
B
Explanation:
A)
B)
C)
D)
231)
231)
The pressure lines on the PH diagram:
A)
Run diagonally from left to right.
B)
Run diagonally from right to left.
C)
Run vertically from top to bottom.
D)
Run horizontally from left to right.
Answer:
D
Explanation:
A)
B)
C)
D)
232)
232)
Why does the condenser line travel farther from left to right than the evaporator line in a
refrigeration cycle PH diagram?
A)
The condenser operates at a higher temperature.
B)
The condenser must get rid of the heat of the compressor as well as the heat gained in the
evaporator.
C)
The condenser operates at a higher pressure.
D)
Extra efficiency is gained by rejecting more heat than is gained.
Answer:
B
Explanation:
A)
B)
C)
D)
60
