In some applications of truck refrigeration, a liquid refrigerant is sprayed directly into the truck box to maintain low temperatures. The liquid refrigerant used is ____.
nitrogen
At extremely low evaporator temperatures, the compression ratio for the compressor becomes too great for single-stage refrigeration.
true
A eutectic solution is a(n)
phase change solution
Truck refrigeration systems are designed to have the capacity to
hold the load temperature when in transit
Where are cascade systems primarily used?
Extra-low temperature range.
Nitrogen changes from a liquid to a vapor at
-320�F
A system that uses two or more refrigeration systems working at the same time and exchanging heat between them to produce ultra-low temperatures, is called a(n) _ system.
cascade
Water-cooled condensers using sea water are usually designed and built to permit periodic cleaning by
brushing the tubes
In order to keep dry ice in the solid form, the temperature of its surroundings can be
-125�F
Cold plates are usually filled with a
All of the above.
Ammonia is extremely toxic to humans and must be used with care. When working with ammonia systems it is often necessary for the technician to wear ____.
all of the above
Seawater-cooled condensers for marine use have
all of the above
Refrigeration systems that use nothing more than a thermostatically controlled solenoid valve feeding a distribution system can use _ or carbon dioxide as their refrigerant.
nitrogen
When products need to be cooled during flight, ice or _ is used.
dry ice
Dry ice is composed of
solidified carbon dioxide
The process where a solid changes directly to a vapor without first becoming a liquid is called _.
sublimation
The system of shipping refrigerated trucks loaded on railcars is known as "_.
piggy back
Nitrogen is not suitable for breathing because it has no _ in it.
oxygen
In a cascade system, the condensing refrigerant in one stage is used to evaporate the refrigerant in another stage.
true
Because of the large capacities of refrigeration systems installed in trucks, the trucks themselves do not need to be insulated from outside ambient temperatures.
false
Refrigerated trucks are equipped with systems that are designed primarily to maintain a product's temperature while being transported.
true
The blast freeze method is done at very low temperatures and a high air _.
velocity
Cargo ship refrigeration units are usually sized with very little reserve capacity.
Selected:
true
The axle-driven refrigeration unit is a new system very commonly used in today's railway refrigeration.
false
The pressure relief valve
is set to relieve the pressure in the boiler below its maximum design pressure
The only place a bleed valve is needed is on top of the boiler.
false
The series loop system is the hydronic system that is found most often, primarily because of the ____.
low installation cost
Hydronic heat circulators are centrifugal pumps.
true
The reason for using zone valves on a hydronic heating system is to ____.
both a & c
Automatic air vents rely on an internal disc that swells when water is sensed.
true
The high-limit control, like the _, is a device that opens and closes its contacts in response to boiler water temperature.
aquastat
Most residences with modern hydronic heating systems use _ baseboard heat transfer for terminal heating units.
finned tube
A column of water 1 ft high exerts a pressure of ____.
0.433 psig
The expansion tank provides a means of removing the air from the system as well as provides ____.
a space for the water expansion and contraction with water temperature changes
Air in a hydronic system can cause ____.
both a &C
An expansion joint is a device used to ____.
allow for expansion and contraction of the loop piping with water temperature changes
The more sections a boiler has, the higher its capacity will be.
true
Hydronic heating systems are systems in which water or _ carries the heat through pipes to the areas to be heated.
steam
It is important to note that the air separator does not remove air from the system.
true
The more common type of expansion tank is the ____ expansion tank.
diaphragm-type
A tankless domestic water system provides hot water from a coil in the boiler.
true
The low-water _ valve is responsible for deenergizing the hydronic system in the event the level of water in the system drops below the desired point.
cut off
A pressure relief valve is set at 30 psig. The valve is constantly opening and flooding the floor. What is causing the relief valve to constantly open?
The system is overfiring.
On systems that use two-port zone valves, excessive pressure in the supply header may result when multiple zone valves _.
closed
Expansion tanks must always be bled from the top until all of the air is removed from it.
false
Pumps generally have a cast-iron body with the impeller and other moving parts made of _ or nonferrous metals.
bronze
A high-limit control on a hot water boiler is needed to ____.
protect the boiler against excessive water temperatures
A series loop hydronic system is not desirable for use in a large residence because ____.
all of the heated water will flow to all rooms
In a geothermal heat pump system, there is a refrigerant loop and a water (water and antifreeze) loop.
true
Open-loop, water-source heat pump systems involve the transfer of heat between a water source and the air or water being circulated to a(n) _ space.
conditioned
The inner tube of heat exchangers of water-source heat pumps have extended surfaces called _, which increase the surface area for better heat transfer.
leads
Scale results in a low head pressure in the cooling mode and high suction pressure in the heating mode.
false
In order to prevent water contamination, wells used for geothermal heat pump systems are grouted.
true
A domestic hot water loop is often used for heating domestic hot water from the hot discharge gas coming from the heat pump's refrigerant compressor.
true
Temperature, quantity, and cleanliness are three important factors that should be addressed when referring to water quality.
true
One of the minor differences between troubleshooting a geothermal heat pump and an air-to-air heat pump is how to gain access to pressures and temperatures in the water or ground loop.
true
Three common types of antifreeze are salts, glycols, and _.
alcohols
What is the temperature differential between water in and water out of a heat exchanger that has transferred 50,000 Btu/h? The flow rate is 10 gallons per minute.
10 deg
A dry well is most commonly used as part of a(n) _ system.
open loop
An advantage of a "parallel flow" configuration of ground loops is ____.
smaller diameter pipes
The hot gas line from the heat pump's compressor can be used to ____.
heat domestic water
When the water and refrigerant in a heat exchanger flow in opposite directions, it is referred to as ____.
counterflow
An advantage of a "series flow" configuration of ground loops is ____.
ease of removing trapped air
Geothermal heat pumps use the _ water as a heat source or a heat sink.
earths
A "dedicated" geothermal well is part of a(n) _ system.
closed-loop
Many coaxial heat exchangers are made of ____.
cupronickel
In a closed-loop system, the plastic water pipes that are buried in the Earth are called ____.
both a & c
Before deciding to purchase or install an open-loop system, the _ must be evaluated first.
water quality
The ground loop configuration that is used when there is a shortage of land is the _.
vertical
In a closed-loop system, the same fluid (water or water and antifreeze) will absorb heat from the ground in the winter and reject the heat to the ground in the summer.
true
Since the Earth's crust is cooler than the air during the summer, it can be used to accept air conditioning heat loads.
true
The _ is nothing more than a large tank that both receives water from the condenser as well as supplying water to the condenser.
buffer tank
The evaporator of a chiller can be used to absorb heat from ____.
a & B
When referring to evaporators, the terms "direct expansion" and "dry type" can be used interchangeably.
true
Thermostatic expansion valves are the only metering devices used in high pressure chillers.
false
The compressors used in low pressure chillers are the ____ type.
centrifugal
Low pressure chillers use either air- or water-cooled condensers.
false
To unload a reciprocating compressor, hot gas bypass across the cylinder is the best method.
false
A benefit of operating a compressor unloaded is ____.
both A&B
Lithium bromide is ideal for use in absorption systems because it is non-corrosive.
false
Two basic categories of chillers are the ____.
compression cycle and absorption
High pressure chillers use either air- or water-cooled condensers.
true
A centrifugal compressor uses ____ for capacity control.
guide vanes
Electronic starters are much smaller than conventional starters.
true
A purge unit ____.
relieves non-condensable gases from the system to the atmosphere
The device that automatically helps to remove non-condensables from a chiller is called a(n) _.
purge unit
A chiller typically cools _ (what liquid?) for the purpose of air conditioning.
water
The refrigerant in an absorption chiller whose source of energy is steam or hot water is _.
water
Speeds up to ____ rpm are used in centrifugal compressors.
30,000
A reciprocating compressor with six cylinders, three banks of two cylinders each, can have its capacity reduced by unloading to ____% of full capacity.
33-1/3
The pressure difference in a low-pressure chiller is produced by a(n) _ compressor.
centrifugal
When a chiller using a low-pressure refrigerant is operating, the low pressure side of the system ____.
is always in a vacuum
Direct expansion evaporators have ____.
an established superheat at the outlet of the evaporator
The pressure difference in an absorption chiller where the source of energy is steam or hot water is produced with the use of a(n) _ solution.
Lithium Bromide
In centrifugal compressors, capacity control is accomplished by the use of _ at the impeller inlet.
guide vanes
The term ____ refers to the process of cooling the circulating condenser water by evaporating the tower water.
adiabatic
Two methods used to aid the evaporation rate of water in a forced or induced draft tower are ____.
splash and wetted-surface (or fill)
Two types of shaft seals used for centrifugal pumps are ____.
stuffing box and mechanical types
A well-designed and installed cooling tower requires only a minimum of maintenance.
false
Larger cooling towers generally use _-type fans.
propeller
When sizing a cooling tower, the tower is sized to handle the cooling load of the conditioned area plus about ____% for heat of compression.
25
Cooling towers are designed to reduce the entering water temperature to within ____�F of the air's wet-bulb temperature.
7
A spray pond would be an example of a(n) _ draft cooling application.
natural
If the blower on a cooling tower breaks down on a hot day, the ____.
Both A&B
A new chemical-free water purification technology is used in cooling towers to ____.
eliminate scale
Distilled water is added to the cooling tower to make up for water lost during blowdown.
false
A blowdown system for a cooling tower ____.
reduces the concentration of sediment in the sump
The purpose of the cooling tower bypass valve is to ____.
help maintain the correct water temperature to the condenser
Natural draft cooling towers usually has an approach temperature of about _�F because of relying only on the winds.
10 deg F
_ allow the motor to soft start and to coast down without abruptly shutting the motor off.
VFDs
Condenser water pumps are normally _ pumps.
centrifugal
Technician "A" says that a cooling tower can reduce the temperature of the water supplied to the condensers to a temperature equal to, but not less than, the wet-bulb temperature of the ambient air. Technician "B" says that a cooling tower's approach temp
Technician "A" is incorrect. Technician "B" is incorrect.
Spray ponds on rooftops have made a comeback in the last few years because they cool the roof and reduce the solar load on the structure.
true
If vortexing occurs, it is an indication that there is not enough air in the tower.
false
The heat that the cooling tower must reject from the water in the chiller is the cooling load of the conditioned area plus the heat of ____.
compression
Natural draft towers and spray ponds are designed to produce a difference in water and air temperatures of ____�F.
10
The two air flow patterns for cooling towers are _ and counterflow.
crossflow
The difference between the entering air wet-bulb temperature and the temperature of the water leaving the tower is called the _.
approach
The condenser water pump is the device that moves the water through the condenser and cooling tower circuit.
true
Ball valves for refrigerant piping are used for larger applications and come in sizes up to about _.
27/8 in..
If the compressor motor megohm value begins to decrease, it is a sign that _ or some other foreign matter may be getting into the system.
moisture
After chemically cleaning a condenser, it is extremely important to make sure that the chemicals are neutralized or the tubes may be damaged.
true
The scroll-chiller compressor needs crankcase heat and it must be energized for the length of time the manufacturer requires, usually_ hours.
24
Water-cooled chillers must have water treatment to ____.
prevent minerals and algae from forming in the water circuit
The safety switch in the chilled water line that is activated by water flow is called a(n) _.
flow switch
The operation of chillers involves starting, running, and stopping the system's components in an orderly manner.
true
If the purge unit on a chiller is operating very frequently, the system may have a leak.
true
Reciprocating chillers have crankcase heaters to ____.
prevent refrigerant migration to the crankcase
A typical chilled water system is designed to operate with a leaving water temperature of ____�F.
45
When a water-cooled chiller is operating normally, it can usually be left unattended, except for which component?
The cooling tower.
Low-pressure chillers operate in a vacuum and will stay in a vacuum if the equipment room is not warm enough to keep the refrigerant warm.
true
The _ creates much less pressure drop through the valve than the globe valve and is a much better application where excess pressure drop is a concern.
gate valve
The technician should also be aware of the _ through the contactors that must be satisfied before startup.
interlock circuit
There should be a ____ test point at the inlet and outlet of any water heat exchanger, chiller, or condenser.
pressure
To remove particles that may be in suspension and circulating in a water circuit, a(n) _ is used.
strainer
What may happen if a lithium-bromide absorption system is started with the cooling water too cold?
crystallization occurs
Centrifugal chillers range in size from ____ tons for a single chiller.
100 - 10,000 tons
The _ is used in water circuits and is a quick-shutoff valve? as it only needs to be turned one-quarter turn from on to off, like a ball valve.
butterfly valve
Chillers manufactured in the last few years all have ____ controls.
electronic control
If an absorption unit is started with very cold water in the cooling tower, the lithium bromide in the unit may _.
chrystalize
If an absorption chiller makes an "ice-crackling" sound, it is an indication that no condenser water is flowing.
False
There are three lines of defense against refrigerant leaks in a service valve: the back seat, the packing gland, and the _.
protective cap
The first step in starting a chilled-water system is to ____.
establish the chilled-water flow
In some applications of truck refrigeration, a liquid refrigerant is sprayed directly into the truck box to maintain low temperatures. The liquid refrigerant used is ____.
nitrogen
At extremely low evaporator temperatures, the compression ratio for the compressor becomes too great for single-stage refrigeration.
TRUE
A eutectic solution is a(n)
phase change solution
Truck refrigeration systems are designed to have the capacity to
hold the load temperature when in transit
Where are cascade systems primarily used?
Extra-low temperature range.
Nitrogen changes from a liquid to a vapor at
-320�F
A system that uses two or more refrigeration systems working at the same time and exchanging heat between them to produce ultra-low temperatures, is called a(n) _ system.
cascade
Water-cooled condensers using sea water are usually designed and built to permit periodic cleaning by
brushing the tubes
In order to keep dry ice in the solid form, the temperature of its surroundings can be
-125�F
Cold plates are usually filled with a
All of the above.
Ammonia is extremely toxic to humans and must be used with care. When working with ammonia systems it is often necessary for the technician to wear ____.
all of the above
Seawater-cooled condensers for marine use have
all of the above
Refrigeration systems that use nothing more than a thermostatically controlled solenoid valve feeding a distribution system can use _ or carbon dioxide as their refrigerant.
nitrogen
When products need to be cooled during flight, ice or _ is used.
dry ice
Dry ice is composed of
solidified carbon dioxide
The process where a solid changes directly to a vapor without first becoming a liquid is called _.
sublimation
The system of shipping refrigerated trucks loaded on railcars is known as "_.
piggy back
Nitrogen is not suitable for breathing because it has no _ in it.
oxygen
In a cascade system, the condensing refrigerant in one stage is used to evaporate the refrigerant in another stage.
TRUE
Because of the large capacities of refrigeration systems installed in trucks, the trucks themselves do not need to be insulated from outside ambient temperatures.
FALSE
Refrigerated trucks are equipped with systems that are designed primarily to maintain a product's temperature while being transported.
TRUE
The blast freeze method is done at very low temperatures and a high air _.
velocity
Cargo ship refrigeration units are usually sized with very little reserve capacity.
Selected:
TRUE
The axle-driven refrigeration unit is a new system very commonly used in today's railway refrigeration.
FALSE
The pressure relief valve
is set to relieve the pressure in the boiler below its maximum design pressure
The only place a bleed valve is needed is on top of the boiler.
FALSE
The series loop system is the hydronic system that is found most often, primarily because of the ____.
low installation cost
Hydronic heat circulators are centrifugal pumps.
TRUE
The reason for using zone valves on a hydronic heating system is to ____.
both a & c
Automatic air vents rely on an internal disc that swells when water is sensed.
TRUE
The high-limit control, like the _, is a device that opens and closes its contacts in response to boiler water temperature.
aquastat
Most residences with modern hydronic heating systems use _ baseboard heat transfer for terminal heating units.
finned tube
A column of water 1 ft high exerts a pressure of ____.
0.433 psig
The expansion tank provides a means of removing the air from the system as well as provides ____.
a space for the water expansion and contraction with water temperature changes
Air in a hydronic system can cause ____.
both a &C
An expansion joint is a device used to ____.
allow for expansion and contraction of the loop piping with water temperature changes
The more sections a boiler has, the higher its capacity will be.
TRUE
Hydronic heating systems are systems in which water or _ carries the heat through pipes to the areas to be heated.
steam
It is important to note that the air separator does not remove air from the system.
TRUE
The more common type of expansion tank is the ____ expansion tank.
diaphragm-type
A tankless domestic water system provides hot water from a coil in the boiler.
TRUE
The low-water _ valve is responsible for deenergizing the hydronic system in the event the level of water in the system drops below the desired point.
cut off
A pressure relief valve is set at 30 psig. The valve is constantly opening and flooding the floor. What is causing the relief valve to constantly open?
The system is overfiring.
On systems that use two-port zone valves, excessive pressure in the supply header may result when multiple zone valves _.
closed
Expansion tanks must always be bled from the top until all of the air is removed from it.
FALSE
Pumps generally have a cast-iron body with the impeller and other moving parts made of _ or nonferrous metals.
bronze
A high-limit control on a hot water boiler is needed to ____.
protect the boiler against excessive water temperatures
A series loop hydronic system is not desirable for use in a large residence because ____.
all of the heated water will flow to all rooms
In a geothermal heat pump system, there is a refrigerant loop and a water (water and antifreeze) loop.
TRUE
Open-loop, water-source heat pump systems involve the transfer of heat between a water source and the air or water being circulated to a(n) _ space.
conditioned
The inner tube of heat exchangers of water-source heat pumps have extended surfaces called _, which increase the surface area for better heat transfer.
leads
Scale results in a low head pressure in the cooling mode and high suction pressure in the heating mode.
FALSE
In order to prevent water contamination, wells used for geothermal heat pump systems are grouted.
TRUE
A domestic hot water loop is often used for heating domestic hot water from the hot discharge gas coming from the heat pump's refrigerant compressor.
TRUE
Temperature, quantity, and cleanliness are three important factors that should be addressed when referring to water quality.
TRUE
One of the minor differences between troubleshooting a geothermal heat pump and an air-to-air heat pump is how to gain access to pressures and temperatures in the water or ground loop.
TRUE
Three common types of antifreeze are salts, glycols, and _.
alcohols
What is the temperature differential between water in and water out of a heat exchanger that has transferred 50,000 Btu/h? The flow rate is 10 gallons per minute.
10 deg
A dry well is most commonly used as part of a(n) _ system.
open loop
An advantage of a "parallel flow" configuration of ground loops is ____.
smaller diameter pipes
The hot gas line from the heat pump's compressor can be used to ____.
heat domestic water
When the water and refrigerant in a heat exchanger flow in opposite directions, it is referred to as ____.
counterflow
An advantage of a "series flow" configuration of ground loops is ____.
ease of removing trapped air
Geothermal heat pumps use the _ water as a heat source or a heat sink.
earths
A "dedicated" geothermal well is part of a(n) _ system.
closed-loop
Many coaxial heat exchangers are made of ____.
cupronickel
In a closed-loop system, the plastic water pipes that are buried in the Earth are called ____.
both a & c
Before deciding to purchase or install an open-loop system, the _ must be evaluated first.
water quality
The ground loop configuration that is used when there is a shortage of land is the _.
vertical
In a closed-loop system, the same fluid (water or water and antifreeze) will absorb heat from the ground in the winter and reject the heat to the ground in the summer.
TRUE
Since the Earth's crust is cooler than the air during the summer, it can be used to accept air conditioning heat loads.
TRUE
The _ is nothing more than a large tank that both receives water from the condenser as well as supplying water to the condenser.
buffer tank
The evaporator of a chiller can be used to absorb heat from ____.
a & B
When referring to evaporators, the terms "direct expansion" and "dry type" can be used interchangeably.
TRUE
Thermostatic expansion valves are the only metering devices used in high pressure chillers.
FALSE
The compressors used in low pressure chillers are the ____ type.
centrifugal
Low pressure chillers use either air- or water-cooled condensers.
FALSE
To unload a reciprocating compressor, hot gas bypass across the cylinder is the best method.
FALSE
A benefit of operating a compressor unloaded is ____.
both A&B
Lithium bromide is ideal for use in absorption systems because it is non-corrosive.
FALSE
Two basic categories of chillers are the ____.
compression cycle and absorption
High pressure chillers use either air- or water-cooled condensers.
TRUE
A centrifugal compressor uses ____ for capacity control.
guide vanes
Electronic starters are much smaller than conventional starters.
TRUE
A purge unit ____.
relieves non-condensable gases from the system to the atmosphere
The device that automatically helps to remove non-condensables from a chiller is called a(n) _.
purge unit
A chiller typically cools _ (what liquid?) for the purpose of air conditioning.
water
The refrigerant in an absorption chiller whose source of energy is steam or hot water is _.
water
Speeds up to ____ rpm are used in centrifugal compressors.
30,000
A reciprocating compressor with six cylinders, three banks of two cylinders each, can have its capacity reduced by unloading to ____% of full capacity.
1933-01-03
The pressure difference in a low-pressure chiller is produced by a(n) _ compressor.
centrifugal
When a chiller using a low-pressure refrigerant is operating, the low pressure side of the system ____.
is always in a vacuum
Direct expansion evaporators have ____.
an established superheat at the outlet of the evaporator
The pressure difference in an absorption chiller where the source of energy is steam or hot water is produced with the use of a(n) _ solution.
Lithium Bromide
In centrifugal compressors, capacity control is accomplished by the use of _ at the impeller inlet.
guide vanes
The term ____ refers to the process of cooling the circulating condenser water by evaporating the tower water.
adiabatic
Two methods used to aid the evaporation rate of water in a forced or induced draft tower are ____.
splash and wetted-surface (or fill)
Two types of shaft seals used for centrifugal pumps are ____.
stuffing box and mechanical types
A well-designed and installed cooling tower requires only a minimum of maintenance.
FALSE
Larger cooling towers generally use _-type fans.
propeller
When sizing a cooling tower, the tower is sized to handle the cooling load of the conditioned area plus about ____% for heat of compression.
25
Cooling towers are designed to reduce the entering water temperature to within ____�F of the air's wet-bulb temperature.
7
A spray pond would be an example of a(n) _ draft cooling application.
natural
If the blower on a cooling tower breaks down on a hot day, the ____.
Both A&B
A new chemical-free water purification technology is used in cooling towers to ____.
eliminate scale
Distilled water is added to the cooling tower to make up for water lost during blowdown.
FALSE
A blowdown system for a cooling tower ____.
reduces the concentration of sediment in the sump
The purpose of the cooling tower bypass valve is to ____.
help maintain the correct water temperature to the condenser
Natural draft cooling towers usually has an approach temperature of about _�F because of relying only on the winds.
10 deg F
_ allow the motor to soft start and to coast down without abruptly shutting the motor off.
VFDs
Condenser water pumps are normally _ pumps.
centrifugal
Technician "A" says that a cooling tower can reduce the temperature of the water supplied to the condensers to a temperature equal to, but not less than, the wet-bulb temperature of the ambient air. Technician "B" says that a cooling tower's approach temp
Technician "A" is incorrect. Technician "B" is incorrect.
Spray ponds on rooftops have made a comeback in the last few years because they cool the roof and reduce the solar load on the structure.
TRUE
If vortexing occurs, it is an indication that there is not enough air in the tower.
FALSE
The heat that the cooling tower must reject from the water in the chiller is the cooling load of the conditioned area plus the heat of ____.
compression
Natural draft towers and spray ponds are designed to produce a difference in water and air temperatures of ____�F.
10
The two air flow patterns for cooling towers are _ and counterflow.
crossflow
The difference between the entering air wet-bulb temperature and the temperature of the water leaving the tower is called the _.
approach
The condenser water pump is the device that moves the water through the condenser and cooling tower circuit.
TRUE
Ball valves for refrigerant piping are used for larger applications and come in sizes up to about _.
27/8 in..
If the compressor motor megohm value begins to decrease, it is a sign that _ or some other foreign matter may be getting into the system.
moisture
After chemically cleaning a condenser, it is extremely important to make sure that the chemicals are neutralized or the tubes may be damaged.
TRUE
The scroll-chiller compressor needs crankcase heat and it must be energized for the length of time the manufacturer requires, usually_ hours.
24
Water-cooled chillers must have water treatment to ____.
prevent minerals and algae from forming in the water circuit
The safety switch in the chilled water line that is activated by water flow is called a(n) _.
flow switch
The operation of chillers involves starting, running, and stopping the system's components in an orderly manner.
TRUE
If the purge unit on a chiller is operating very frequently, the system may have a leak.
TRUE
Reciprocating chillers have crankcase heaters to ____.
prevent refrigerant migration to the crankcase
A typical chilled water system is designed to operate with a leaving water temperature of ____�F.
45
When a water-cooled chiller is operating normally, it can usually be left unattended, except for which component?
The cooling tower.
Low-pressure chillers operate in a vacuum and will stay in a vacuum if the equipment room is not warm enough to keep the refrigerant warm.
TRUE
The _ creates much less pressure drop through the valve than the globe valve and is a much better application where excess pressure drop is a concern.
gate valve
The technician should also be aware of the _ through the contactors that must be satisfied before startup.
interlock circuit
There should be a ____ test point at the inlet and outlet of any water heat exchanger, chiller, or condenser.
pressure
To remove particles that may be in suspension and circulating in a water circuit, a(n) _ is used.
strainer
What may happen if a lithium-bromide absorption system is started with the cooling water too cold?
crystallization occurs
Centrifugal chillers range in size from ____ tons for a single chiller.
100 - 10,000 tons
The _ is used in water circuits and is a quick-shutoff valve? as it only needs to be turned one-quarter turn from on to off, like a ball valve.
butterfly valve
Chillers manufactured in the last few years all have ____ controls.
electronic control
If an absorption unit is started with very cold water in the cooling tower, the lithium bromide in the unit may _.
chrystalize
If an absorption chiller makes an "ice-crackling" sound, it is an indication that no condenser water is flowing.
FALSE
There are three lines of defense against refrigerant leaks in a service valve: the back seat, the packing gland, and the _.
protective cap
The first step in starting a chilled-water system is to ____.
establish the chilled-water flow