80)
80)
A weeping relief valve on a hot water boiler may be an indication of:
A)
Low return water temperature.
B)
A water–logged expansion tank problem.
C)
An extinguished pilot light.
D)
A circulating pump that is running continuously.
Answer:
B
Explanation:
81)
81)
How is a hot water boiler pressure relief valve tested?
A)
By slowly adding nitrogen pressure until the relief valve opens
B)
By checking the continuity of its operating coil
C)
By jumping the aquastat and limit, forcing the boiler to operate until the pressure relief
valve opens
D)
By lifting the lever located on top of the relief valve
Answer:
D
Explanation:
82)
82)
What is the maximum water temperature for a low–pressure water boiler?
A)
150°F
B)
200°F
C)
250°F
D)
180°F
Answer:
C
Explanation:
83)
83)
What is the difference between a fire tube and a water tube boiler?
A)
Fire tube boilers are fueled with gas or oil, and water tube boilers are fueled with steam.
B)
Water is outside the tubes of a water tube boiler and inside the tubes of a fire tube boiler.
C)
Fire tubes are manufactured using heat and flames, and water tubes are manufactured
using high–velocity jets of water.
D)
Water is inside the tubes of a water tube boiler and outside the tubes of a fire tube boiler.
Answer:
D
Explanation:
21
84)
84)
Why is it desirable to have a minimum water temperature entering the boiler?
A)
To increase combustion efficiency
B)
To reduce the load on the boiler
C)
To prevent condensation in the flue
D)
To prevent downdrafts in the flue
Answer:
C
Explanation:
85)
85)
What is the maximum working pressure for a low–pressure steam boiler?
A)
160 psi
B)
100 psi
C)
15 psi
D)
10 psi
Answer:
C
Explanation:
86)
86)
How can a hot water boiler heat water to 250°F and not boil the water?
A)
Water treatment is added whose primary purpose is to raise the boiling point of the water.
B)
The system is under enough pressure to raise the boiling point above the water temperature
in the boiler.
C)
Hot water boilers cannot maintain 250°F water without boiling the water.
D)
The water does boil, but the steam is vented to the air.
Answer:
B
Explanation:
87)
87)
What kind of expansion tank must be installed above the highest terminal unit?
A)
Closed type
B)
Pressure–relief type
C)
Diaphragm type
D)
Open type
Answer:
D
Explanation:
22
88)
88)
In order to facilitate air removal, a diaphragm–type expansion tank should be placed:
A)
On the discharge side of the boiler.
B)
On the supply aide of the boiler.
C)
Above the boiler, below the roofline.
D)
Above the highest terminal unit.
Answer:
A
Explanation:
89)
89)
Where should air vents be located in a hot water heating system?
A)
Leaving the circulator pump
B)
Air vents need to be placed at high points of the system and on terminal units.
C)
Air vents need to be placed at low points of the system and on terminal units.
D)
Entering the circulator pump
Answer:
B
Explanation:
90)
90)
What is the typical pressure setting for a relief valve at on a residential hot water boiler?
A)
15 psig
B)
30 psig
C)
160 psig
D)
12 psig
Answer:
B
Explanation:
91)
91)
What is the normal charge on a residential diaphragm type of expansion tank?
A)
160 psig
B)
12 psig
C)
60 psig
D)
30 psig
Answer:
B
Explanation:
23
92)
92)
Why is low water a dangerous condition for a boiler?
A)
A boiler that is low on water will have higher–than–normal internal mineral deposits.
B)
A boiler that is low on water can create steam pressure and explode as a result.
C)
A boiler that is low on water can cause excessive energy bills.
D)
A boiler that is low on water can cause the burners to overheat.
Answer:
B
Explanation:
93)
93)
Which kind of cooling tower draws or pushes the air across the water, rather than up through it?
A)
Forced–draft
B)
Induced–draft
C)
Counterflow
D)
Crossflow
Answer:
D
Explanation:
94)
94)
A cooling tower with its fan located in the air stream leaving the tower, drawing the air through
the tower, is:
A)
An induced–draft cooling tower.
B)
A natural–draft cooling tower.
C)
A hybrid–draft cooling tower.
D)
A forced–draft cooling tower.
Answer:
A
Explanation:
95)
95)
The pump should be located between the tower and the chiller so that:
A)
The water is “pulled” from the condenser and “pushed” into the tower.
B)
The inlet for the sump can be piped to both the sump and the condenser.
C)
The inlet for the pump is above the water level in the sump.
D)
The water is “pulled” from the tower and “pushed” through the condenser.
Answer:
D
Explanation:
24
96)
96)
What is an acceptable amount of drift?
A)
2 to 5 percent
B)
0.1 to 0.3 percent
C)
1 to 3 percent
D)
0.5 to 0.6 percent
Answer:
B
Explanation:
97)
97)
An evaporative condenser:
A)
Is really just another name for evaporator.
B)
Works by evaporating refrigerant to cool the condenser coil.
C)
Works by evaporating water to cool the condenser coil.
D)
Cools air through the evaporation of refrigerant inside the condenser.
Answer:
C
Explanation:
98)
98)
A cooling tower in which air flow is produced by natural convection due to the density difference
between the heated air in the tower and the cooler outside air is called:
A)
A mechanical draft tower.
B)
A draft–free tower.
C)
An atmospheric draft tower.
D)
An induced draft tower.
Answer:
C
Explanation:
99)
99)
Antifreeze should be used on the cooling tower even if the plan is to drain the tower for cold
spells, because:
A)
Most municipalities require it.
B)
A sudden cold spell can freeze the system.
C)
Antifreeze descales the pipes.
D)
Antifreeze aids in draining the tower.
Answer:
B
Explanation:
25
100)
100)
What is the lowest temperature a cooling tower can produce?
A)
A few degrees above the incoming air wet–bulb temperature
B)
32°F, the temperature where water freezes
C)
A few degrees above the incoming air temperature
D)
Down to a few degrees above absolute zero if applied correctly
Answer:
A
Explanation:
101)
101)
The temperature difference between the temperature of the cold water leaving the cooling tower
and the wet–bulb temperature of the air entering the tower is known as:
A)
Cooling range.
B)
Wet–bulb depression.
C)
Approach.
D)
Heat load.
Answer:
C
Explanation:
102)
102)
The temperature difference between the hot water entering the tower and the cold water leaving
the tower is known as:
A)
Approach.
B)
Heat load.
C)
Cooling range.
D)
Wet–bulb depression.
Answer:
C
Explanation:
103)
103)
A cooling tower with its fan located in the air stream entering the tower, blowing the air through
the tower, is:
A)
An induced–draft cooling tower.
B)
A hybrid–draft cooling tower.
C)
A natural–draft cooling tower.
D)
A forced–draft cooling tower.
Answer:
D
Explanation:
26
104)
104)
Which of the following statements regarding cooling tower operations is correct?
A)
On very dry days, the cooling tower can cool the water below the wet–bulb temperature.
B)
On dry days, the cooling tower can cool the water temperature below the ambient
temperature.
C)
When the water evaporates from the wet–bulb thermometer, the temperature rises.
D)
The cooling tower operation depends on the dry–bulb temperature.
Answer:
B
Explanation:
105)
105)
What is an advantage of a crossflow tower?
A)
A cross flow tower can be configured for a lower height.
B)
Cross flow cooling towers can employ ECM blower motors.
C)
Cross flow cooling towers have variable–pitch air inlet vanes to provide more efficient
airflow through the tower.
D)
The discharge air can be ducted into conditioned space in the winter to provide free heat
and humidification.
Answer:
A
Explanation:
106)
106)
Which of the following statements regarding mechanical–draft cooling towers is correct?
A)
Only one fan is required for an induced–draft counterflow tower.
B)
Cross flow cooling towers may be used for indoor applications.
C)
Three fans are required for a forced–draft crossflow cooling tower.
D)
Counterflow towers are shorter and wider than crossflow towers.
Answer:
B
Explanation:
27
107)
107)
Water treatment is necessary to protect the system components against:
A)
Fouling, freezing, and evaporating.
B)
Scale, corrosion, and fouling.
C)
Hypothermia, outgassing, and corrosion.
D)
Freezing, evaporation, and sublimation.
Answer:
B
Explanation:
108)
108)
Draining a small fraction of circulating water from the tower sump to prevent the buildup and
concentration of scale forming minerals is called:
A)
Sump purging.
B)
Blowdown.
C)
Desalinization.
D)
Draindown.
Answer:
B
Explanation:
109)
109)
Cooling towers in which the water circulating in the tower is separate from the water circulating
through the condenser are called:
A)
Regenerative cooling towers.
B)
Evaporative cooling towers.
C)
Closed–loop cooling towers.
D)
Open–loop cooling towers.
Answer:
C
Explanation:
110)
110)
The rate of water evaporation in a cooling water tower is approximately:
A)
10 percent of the water supplied to the tower for every 10 degrees the water is cooled.
B)
1 percent of the water supplied to the tower for every 10 degrees the water is cooled.
C)
1 gallon of the water per hour for every 10 degrees the water is cooled.
D)
10 gallons of water per hour for every 10 degrees the water is cooled.
Answer:
B
Explanation:
28
111)
111)
The small amount of water lost in the form of fine droplets carried away by the circulating air is
called:
A)
Plume.
B)
Tail.
C)
Drift.
D)
Carryover.
Answer:
C
Explanation:
112)
112)
Heat absorbed by the water during evaporation is called:
A)
Dry heat.
B)
Latent heat.
C)
Specific heat.
D)
Sensible heat.
Answer:
B
Explanation:
113)
113)
To ensure priming, the pump should be installed so that the pump suction is lower than the tower
basin’s:
A)
Inlet valve.
B)
Cold–water level.
C)
Air–inlet fan.
D)
Deck material.
Answer:
B
Explanation:
114)
114)
Why should an inside sump be included in the cooling tower piping?
A)
It allows the tower to be supersaturated when needed.
B)
It increases tower efficiency by lowering the wet–bulb temperature.
C)
It shuts down the tower fan when it is not needed.
D)
It provides a cooling tower bypass in freezing weather.
Answer:
D
Explanation:
29
115)
115)
Mechanical draft towers are categorized as:
A)
Packaged or split–system.
B)
Induced–draft or forced–draft.
C)
Upflow or downflow.
D)
Low–pressure or high–pressure.
Answer:
B
Explanation:
116)
116)
Why is the evaporative condenser the least popular?
A)
It is most effective in larger applications.
B)
It requires special training to run effectively.
C)
It has higher maintenance requirements.
D)
It is too large for most applications.
Answer:
C
Explanation:
117)
117)
What should be drained, cleaned, and flushed on a regular basis?
A)
The cooling tower basin
B)
The sump and all water lines
C)
The compressor and blower
D)
The evaporative condenser
Answer:
A
Explanation:
118)
118)
What is makeup water?
A)
The water required to initially fill the cooling tower
B)
Water added to replace water lost by evaporation, drift, and blowdown
C)
Water added to correct system inefficiencies
D)
The water circulated by the cooling tower pump
Answer:
B
Explanation:
30
119)
119)
What is the advantage of using multiple compressors on a supermarket rack system?
A)
The compressors can operate at a higher compression ratio as a parallel group.
B)
Extra compressors provide backup in case one quits working.
C)
Using multiple parallel compressors makes the use of multiple refrigerants possible.
D)
System capacity can match refrigeration loads, which vary over a wide range.
Answer:
D
Explanation:
120)
120)
What is the purpose of the door switch on a walk–in freezer?
A)
To prevent warm air from entering the case by shutting off the fans when the door is
opened
B)
To turn on the system to offset the added heat from opening the door
C)
To turn on the light in the case when the door is opened
D)
To energize the interior heaters to make the case a more comfortable temperature
Answer:
A
Explanation:
121)
121)
The essential elements of a single–component system refrigeration system, in order, are:
A)
Evaporator, compressor, condenser, and metering device.
B)
Metering device, compressor, evaporator, and condenser.
C)
Condenser, compressor, metering device, and evaporator.
D)
Compressor, evaporator, metering device, and condenser.
Answer:
A
Explanation:
31
122)
122)
Three common methods of controlling evaporator temperature are:
A)
Evaporator pressure regulator, crankcase pressure regulator, and compressor speed control.
B)
High–pressure cutout, crankcase pressure regulator, and conventional thermostat.
C)
Conventional thermostat, a suction pressure cut–out control, or an evaporator pressure
regulator.
D)
Compressor speed control, electric strip reheat, and hot gas bypass.
Answer:
C
Explanation:
123)
123)
What must be considered when performing a heat load calculation for a walk–in cooler or freezer?
A)
The volume of the case, the temperature to be maintained, and the air changes per hour
B)
The style of evaporator, the box temperature, and the type of refrigerant
C)
Heat transmission, air infiltration, and product load
D)
Heat gain through the walls, floor, and ceiling
Answer:
C
Explanation:
124)
124)
What are the broad areas that commercial refrigeration equipment is grouped in based on the
evaporator coil temperature?
A)
Perishable frozen and perishable nonfrozen
B)
Refrigerator and freezers
C)
High, medium, low, and cryogenic temperatures
D)
Frosting, nonfrosting, and defrosting
Answer:
C
Explanation:
125)
125)
What is the approximate ventilation requirement for low–temperature, air–cooled condensing
units located in indoors?
A)
200 CFM per 1,000 BTU
B)
465 CFM per 1,000 BTU
C)
400 CFM per 1,000 BTU
D)
165 CFM per 1,000 BTU
Answer:
A
Explanation:
32
126)
126)
Why is a check valve installed in the suction line of the lowest–temperature coil in a
multiple–evaporator system?
A)
To allow the coil to be isolated from other evaporator coils when checking the operating of
the evaporator pressure regulator
B)
To ensure that the refrigerant is completely vaporized before leaving the evaporator
C)
To prevent refrigerant migration from the higher–temperature–and–pressure coil to the
lower–temperature and–pressure coil
D)
To allow the service technician to check the operation of the system
Answer:
C
Explanation:
127)
127)
Why would a 35°F medium–temperature case need to defrost?
A)
A 35°F temperature case does not need to defrost.
B)
The store manager might decide to maintain a lower box temperature.
C)
It is common for water to freeze at 35° in higher elevations.
D)
The coil temperature for a 35°F box operates below freezing.
Answer:
D
Explanation:
128)
128)
The first step in selecting commercial refrigeration equipment for a new installation is:
A)
Compile a list of components already in inventory so that you can see what you will have to
choose from.
B)
Compile a list of component prices in order to determine how large a system you can afford.
C)
Perform a heat load calculation to determine the required BTU capacity of the system.
D)
Select the compressor because all other components will be sized to match it.
Answer:
C
Explanation:
33
129)
129)
A refrigerated case that maintains a temperature of 28°F would be classified as:
A)
A medium–temperature system.
B)
A high–temperature system.
C)
A low–temperature system.
D)
A cryogenic system.
Answer:
A
Explanation:
130)
130)
What is the normal storage temperature for food items like milk, cheese, fresh fruits, and
vegetables?
A)
From 25°F to 35°F
B)
from 40°F to 50°F
C)
From 0°F to 32°F
D)
from 32°F to 40°F
Answer:
D
Explanation:
131)
131)
When multiple compressors are installed in parallel on the same refrigeration system, provisions
must be made to ensure that:
A)
The oil level is correct in all compressors.
B)
All compressors start and stop at the same time.
C)
All compressors pull the same amount of current.
D)
The refrigerant flow is equal through all compressors.
Answer:
A
Explanation:
132)
132)
The defrost cycle is normally terminated:
A)
Based strictly on temperature to ensure that all the frost has melted.
B)
Based strictly on pressure to ensure safe operation for the compressor.
C)
Based strictly on defrost time to reduce the chance of sensor inaccuracy.
D)
Based on either temperature, pressure, or time.
Answer:
D
Explanation:
34
133)
133)
What is commonly used to control defrost operations?
A)
Defrost timer
B)
Electric heater
C)
Thermometer
D)
Door switch
Answer:
A
Explanation:
134)
134)
What refrigeration component makes it possible to use a single compressor to control multiple
cases at different temperatures?
A)
Liquid solenoid valve
B)
Crankcase pressure regulator
C)
Evaporator pressure regulator
D)
Suction line accumulator
Answer:
C
Explanation:
135)
135)
A system that maintains temperatures of –250°F and below is a(n):
A)
Ultra–low–temperature system.
B)
Low–temperature system.
C)
Cryogenic system.
D)
Absorption system.
Answer:
C
Explanation:
136)
136)
Why should the evaporator NOT be installed above the door in a walk–in cooler or freezer?
A)
It will draw in warm, humid air and frost more quickly.
B)
There is no restriction for this location.
C)
It will run constantly.
D)
It may cause problems for the store owner.
Answer:
A
Explanation:
35
137)
137)
How is a smoke candle used when troubleshooting an open display case?
A)
It helps technicians trace the flow of refrigerant through the case.
B)
Smoke candles are used to calibrate the case modulation damper.
C)
It helps locate refrigerant leaks.
D)
It shows the air curtain pattern.
Answer:
D
Explanation:
138)
138)
Where do commercial refrigeration “rack” systems get their name?
A)
RACK stands for Refrigeration Air Conditioning Kontrol.
B)
They use multiple individual condensing units mounted on a large rack outside.
C)
They use multiple compressors mounted in a row on a rack.
D)
They were originally developed by Refrigeration of Ackworth Corporation.
Answer:
C
Explanation:
139)
139)
A refrigeration system that uses the evaporator of a higher–temperature system to cool the
condenser of a lower–temperature refrigeration system is called a:
A)
Transcritical system.
B)
Cascade system.
C)
Subordinate system.
D)
Supercritical system.
Answer:
B
Explanation:
140)
140)
How does increased store humidity affect the operation of the refrigerated cases?
A)
Operation of the refrigerated cases is unaffected by humidity because they are only
providing sensible cooling.
B)
Refrigeration capacity is unaffected, but the food hydration cycles are decreased.
C)
Operating time is decreased and efficiency increased because of the natural cooling effect of
the moist air.
D)
Operating time increases and efficiency decreases due to increased coil frosting.
Answer:
D
Explanation:
36
141)
141)
A parallel heat reclaim system primarily recovers:
A)
Latent heat from the refrigerant.
B)
Sensible heat from the refrigerant.
C)
Both sensible and latent heat from the refrigerant.
Answer:
C
Explanation:
142)
142)
Where is the refrigerant piping run from a rack system to the individual refrigerated cases?
A)
Refrigerant piping is not necessary because rack systems are self–contained.
B)
Through an exterior wall
C)
In trenches under the floor
D)
On top of the floor under a protective metal cover
Answer:
C
Explanation:
143)
143)
The airflow on a single–deck coffin–style open display case:
A)
Travels lengthwise from one end to the other.
B)
Is across the top of the case.
C)
Is only on the bottom of the case.
D)
Is all around the product.
Answer:
B
Explanation:
144)
144)
What is the primary design challenge for CO2 refrigeration systems?
A)
The high operating pressures of CO2 refrigerant
B)
CO2 refrigerant operates in a vacuum at low temperatures.
C)
The high GWP of CO2 refrigerant
D)
The high refrigerant cost
Answer:
A
Explanation:
37
145)
145)
A series heat reclaim system primarily recovers:
A)
Latent heat from the refrigerant.
B)
Sensible heat from the refrigerant.
C)
Both sensible and latent heat from the refrigerant.
Answer:
B
Explanation:
146)
146)
Refrigeration components required for rack systems that are not needed for single–component
systems include:
A)
Suction and discharge valves.
B)
Filter driers and sight glasses.
C)
Suction line accumulators and liquid receivers.
D)
Oil separators and oil level controls.
Answer:
D
Explanation:
147)
147)
The rack–type system is the most common configuration for which type of system?
A)
Multiplex
B)
Direct–expansion
C)
Distributed
D)
Secondary–loop
Answer:
A
Explanation:
148)
148)
A refrigeration cycle in which the high side is above the critical point and the low side is below the
critical point is called a:
A)
Subcritical system.
B)
Transcritical system.
C)
Supercritical system.
D)
Noncritical system.
Answer:
B
Explanation:
38
149)
149)
What type of refrigerants are normally used in CO2 cascade refrigeration systems?
A)
CO2 refrigerant in the high–temperature system and HFC refrigerant in the
low–temperature system
B)
HFC refrigerant mixed with CO2 in both systems
C)
CO2 refrigerant in both the high– and low–temperature systems
D)
HFC refrigerant in the high–temperature system and CO2 in the low–temperature system
Answer:
D
Explanation:
150)
150)
Which type of system reduces the total amount of refrigerant charge required?
A)
Direct–expansion
B)
Distributed
C)
Secondary–loop
D)
Multiplex
Answer:
C
Explanation:
151)
151)
Natural defrosting accomplished by:
A)
Leaving the case fans operating and shutting off the compressor.
B)
Keeping the compressor running and bypassing hot gas to the condenser.
C)
Shutting off the compressor and energizing electric defrost heaters.
D)
Keeping the compressor running and bypassing hot gas to the evaporator.
Answer:
A
Explanation:
152)
152)
In series heat–reclaim systems, what happens to the heat from the refrigerant in the compressor
discharge line?
A)
It flows directly to the condenser.
B)
It is used to preheat the air for the store’s HVAC system.
C)
It is used to cool the air in the store‘s HVAC system.
D)
It flows to the heat–reclaim coil and condenser.
Answer:
B
Explanation:
39
153)
153)
Open display cases are designed:
A)
To freeze liquid products in less than an hour.
B)
To pull down warm products to refrigerated temperatures.
C)
To keep product at the same temperature at which it enters the case.
D)
To display products that do not need refrigerating.
Answer:
C
Explanation:
154)
154)
A refrigeration cycle in which the entire process takes place above the critical point is called a:
A)
Subcritical system.
B)
Transcritical system.
C)
Supercritical system.
D)
Noncritical system.
Answer:
C
Explanation:
155)
155)
What is an uneven rack system?
A)
A rack that has different–capacity compressors
B)
A rack that has multiple tiers to hold more compressors
C)
A system that uses a rack that is sloped to aid oil return
D)
A rack that is not properly balanced
Answer:
A
Explanation:
156)
156)
In which system are both the sensible and latent heat recovered from the refrigerant?
A)
Parallel
B)
Series
C)
Hydronic
D)
Hydroponic
Answer:
A
Explanation:
40