Question 1

When a water-cooled chiller is operating normally, it can usually be left unattended, except for which component?
A) The condenser.
B) The evaporator.
C) The metering device.
D) The cooling tower.

Accepted Answer

The cooling tower requires regular monitoring and maintenance to ensure proper operation, as it is exposed to environmental conditions and can be prone to issues like scaling, fouling, and biological growth.

Question 2

The ____________________ is used in water circuits and is a quick-shutoff valve̶ as it only needs to be turned one-quarter turn from on to off, like a ball valve.

Accepted Answer

butterfly valve

Question 3

The safety switch in the chilled water line that is activated by water flow is called a(n) ____________________.

Accepted Answer

flow switch

Question 4

After chemically cleaning a condenser, it is extremely important to make sure that the chemicals are neutralized or the tubes may be damaged.

Accepted Answer

Chemicals used for cleaning a condenser can be highly corrosive and if not properly neutralized can cause damage to the tubes. It is important to thoroughly flush the condenser with water after cleaning and then confirm that the pH level of the water is neutral before returning the condenser to service.

Question 5

The first step in starting a chilled-water system is to ____.
A) activate the compressor unloading system
B) establish the chilled-water flow
C) activate the condenser heat removal system
D) start the compressor operation sequence

Accepted Answer

Before any other component can be activated in a chilled-water system, the chilled-water flow must be established. This ensures that there is adequate water flow throughout the system and helps prevent damage to the components. Activating the compressor unloading system, condenser heat removal system, or compressor operation sequence before establishing the chilled-water flow could result in damage to the system.

Question 6

Ball valves for refrigerant piping are used for larger applications and come in sizes up to about   ____________________ .

Accepted Answer

The answer of Ball valves for refrigerant piping are used...

Question 7

There should be a ____ test point at the inlet and outlet of any water heat exchanger, chiller, or condenser.
A) temperature
B) pressure
C) vapor
D) moisture

Accepted Answer

The answer of There should be a ____ test point...

Question 8

The operation of chillers involves starting, running, and stopping the system's components in an orderly manner.

Accepted Answer

The operation of chillers involves starting, running, and stopping the system's components in a specific sequence to ensure proper function and efficiency.

Question 9

Chillers manufactured in the last few years all have ____ controls.
A) electronic
B) hydraulic
C) pneumatic
D) pressure-based

Accepted Answer

Electronic controls have become standard in recent years due to their reliability, precision, and ease of use. Hydraulic and pneumatic controls are older technologies that have largely been replaced by electronic controls. Pressure-based controls may be used as part of an electronic control system, but they are not typically the primary control mechanism for chillers.

Question 10

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.

Accepted Answer

Low-pressure chillers operate under a vacuum to facilitate the boiling of the refrigerant at a lower temperature and pressure. If the equipment room is too cold, the refrigerant may not absorb enough heat to vaporize, causing the system to remain under vacuum conditions.

Question 11

Centrifugal chillers range in size from ____ tons for a single chiller.
A) 10 to 50
B) 10 to 80
C) 50 to 500
D) 100 to 10,000

Accepted Answer

Centrifugal chillers can range in size from 100 to 10,000 tons for a single chiller, accommodating large-scale cooling needs such as those found in commercial and industrial applications.

Question 12

If an absorption chiller makes an "ice-crackling" sound, it is an indication that no condenser water is flowing.

Accepted Answer

The "ice-crackling" sound in an absorption chiller typically indicates the presence of non-condensable gases in the system, not the absence of condenser water flow. Non-condensable gases can reduce efficiency and indicate a need for system maintenance.

Question 13

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.

Accepted Answer

The answer of The ____________________ creates much less pressure drop...

Question 14

Water-cooled chillers must have water treatment to ____.
A) increase the pH content of the water in the sump
B) decrease the pH content of the water in the sump
C) prevent minerals and algae from forming in the water circuit
D) help preheat the water in the condenser water circuit

Accepted Answer

Water-cooled chillers need water treatment to prevent minerals and algae from forming in the water circuit, which can cause damage to the chiller and reduce its efficiency. Treatment can include using chemicals to control pH levels, adding biocides to prevent biological growth, and implementing filters or softeners to remove impurities. pH levels should be maintained within a specific range, typically between 7.0 and 9.0, but increasing or decreasing the pH content of the water in the sump is not the primary purpose of water treatment in chillers. Preheating the water in the condenser water circuit is typically done with heat recovery systems or other separate equipment, not through water treatment.

Question 15

The scroll-chiller compressor needs crankcase heat and it must be energized for the length of time the manufacturer requires, usually____________________ hours.

Accepted Answer

The answer of The scroll-chiller compressor needs crankcase heat and...

Question 16

What may happen if a lithium-bromide absorption system is started with the cooling water too cold?
A) High head pressure in the system.
B) Low head pressure in the absorber.
C) Removal of system load, compressor cylinders will unload.
D) Crystallization occurs.

Accepted Answer

If the cooling water is too cold, it can cause the lithium-bromide solution to crystallize, which can damage the system and affect its performance. Therefore, it is important to ensure that the cooling water temperature is within the specified range before starting the absorption system.

Question 17

If the purge unit on a chiller is operating very frequently, the system may have a leak.

Accepted Answer

If the purge unit operates frequently, it indicates that there is a higher level of non-condensable gases in the system, which can be caused by a refrigerant leak.

Question 18

A typical chilled water system is designed to operate with a leaving water temperature of ____°F.
A) 35
B) 40
C) 45
D) 50

Accepted Answer

A typical chilled water system is designed to operate with a leaving water temperature of 45°F, which is standard for many HVAC systems to ensure efficient cooling.

Question 19

Reciprocating chillers have crankcase heaters to ____.
A) preheat the chilled water for better efficiency
B) prevent refrigerant migration to the crankcase
C) preheat the compressor bearings for longer wear
D) minimize condenser subcooling

Accepted Answer

Crankcase heaters are used to prevent refrigerant migration to the crankcase during off-cycle periods. Refrigerant can migrate to the crankcase due to temperature differences between the evaporator and compressor during off-cycle periods, which can lead to compressor damage if not prevented.

Question 20

The technician should also be aware of the ____________________ through the contactors that must be satisfied before startup.

Accepted Answer

The answer of The technician should also be aware of...

Quiz 49: Operation, Maintenance, and Troubleshooting of Chilled-Water Air Conditioning Systems

When a water-cooled chiller is operating normally, it can usually be left unattended, except for which component?

The ____________________ is used in water circuits and is a quick-shutoff valve̶ as it only needs to be turned one-quarter turn from on to off, like a ball valve.

The safety switch in the chilled water line that is activated by water flow is called a(n) ____________________.

After chemically cleaning a condenser, it is extremely important to make sure that the chemicals are neutralized or the tubes may be damaged.

The first step in starting a chilled-water system is to ____.

Ball valves for refrigerant piping are used for larger applications and come in sizes up to about ____________________ .

There should be a ____ test point at the inlet and outlet of any water heat exchanger, chiller, or condenser.

The operation of chillers involves starting, running, and stopping the system's components in an orderly manner.

Chillers manufactured in the last few years all have ____ controls.

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.

Centrifugal chillers range in size from ____ tons for a single chiller.

If an absorption chiller makes an "ice-crackling" sound, it is an indication that no condenser water is flowing.

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.

Water-cooled chillers must have water treatment to ____.

The scroll-chiller compressor needs crankcase heat and it must be energized for the length of time the manufacturer requires, usually____________________ hours.

What may happen if a lithium-bromide absorption system is started with the cooling water too cold?

If the purge unit on a chiller is operating very frequently, the system may have a leak.

A typical chilled water system is designed to operate with a leaving water temperature of ____°F.

Reciprocating chillers have crankcase heaters to ____.

The technician should also be aware of the ____________________ through the contactors that must be satisfied before startup.