Chiller stuff

For each 1°F of added sub cooling, the efficiency of a system will increase by approximately

1%

Of the following represents the most complete and accurate list of possible system capacities for a chilled water system that is equipped with one 10 ton and one 15 ton scroll compressor

10 tons , 15 tons, 25 tons

The typical condensing temperature for the refrigerant in a water cooled chilled water system is

105°F

The design temperature difference between the chilled water supply to the building in the water, returning to the system from the building is

10°F

The ruptured disc on a low-pressure chiller typically releases pressure at

15 psig

If a cooling tower rejects 100 tons of heat, approximately how much of the rejected heat is attributed to the systems compressor

20 tons

A chiller barrel that has three phases will most likely operate with a design approach temperature of about

5°F

Which of the following most closely represents the concentration of LI-BR in a absorption system

60% LI 40% distilled water

What is the approach for a R - 410A chilled water system that produces 43°F water when it operates with an evaporator saturation pressure at 112 PSIG

6° F

If the outside ambient temperature has a dry bulb temperature of 95°F in a wet bulb temperature of 75°F what is the cooling towers approach temperature if the water is leaving the tower at 82°F

7°F

The superheat maintained by thermostatic expansion valve is typically between

8°F - 12°F

In a gearbox or a transmission drive assembly on a cooling tower, the motor shaft in the fan shaft or an angle of _________ degrees with each other

90°F

For an approach temperature of 10°F what is the temperature of the water leaving a condenser if the condenser saturation pressure is 344 PSIG for a R410A system

95°F

Most reciprocating compressors have

A crankcase heater

On a base mounted pump,

A flexible, coupling or connector is positioned between the pump and the motor

Which of the following best describes a 2 Gear drive assembly on a centrifugal compressor

A larger drive gear and a smaller driven gear

When pump cavitation occurs

A partial vacuum is created and the pumps noise level increases

Which of the following components can be found in a cooling tower sump

A water heater and strainer

Low side system leaks in a low-pressure chiller will often result in

Air being pulled into a system

Which of the following best describes the bearings on a centrifugal compressor?

Babbitt construction and steel drive

Encapsulation and electroporation are two methods that can be used to control

Bacterial growth in a cooling tower

In a cooling tower blower assembly, why are bevel gears preferred over non-beveled gears

Beveled gears have more surface area between the mating surfaces

Makeup is required in cooling towers in order to of

Both evaporation and drift

Which of the following is true regarding forced draft and induced draft cooling towers

Both types of cooling towers. Use mechanical fans in blower to move air through them

When condenser tubes become fouled, they may be cleaned by a

Brass brush

Which of the following best describes a centrifugal pump on a cooling tower

Brass or bronze impeller mounted on a stainless steel shaft

All low side chillers use which type of compressor

Centrifugal

What system component is used to move water through the condenser and cooling tower

Centrifugal pump

Regarding cooling towers, a foot valve is a type of

Check valve

A technician can verify water flow through the condenser of a chiller by

Checking the pressure dropped from the inlet to the outlet

What system components must be started before the compressor in a chilled water system centrifugal chiller

Chilled water pump, condenser water, pump, and the oil pump

The portion of a chilled water system that cools the water that is used to cool the building is referred to as

Chiller barrel

All of the following methods can be used to control the capacity of a reciprocating compressor except

Constant suction

What component is incorporated into the marine water boxes to direct water through a shell and tube heat exchanger

Converters

Evaporator is that operate within established amount of superheat are referred to as

Direct expansion evaporators

How does a centrifugal compressor create the pressure differential needed to move refrigerant through the system?

Fan like action

When referring to cooling tower construction, the acronym FRP stands

Fiber reinforced plastic

The circuit is used to energize the chillers compressor is referred to

Field control circuit

List three methods that can be used to control the level of water in the sump of a cooling tower

Float and valve, float switch and solenoid,electronic water level control

Corrosion in a cooling tower comes from all of the following except

Hard water

Instead of using a compressor, in absorption air-conditioning chiller uses which of the following as its driven force

Heat

The two float take me to devices are there

High side float and low side float

If a low-pressure chiller has a low side leak, which of the following will most likely result

High side pressure and low suction pressure

Insufficient water flow through a cooling tower can result in

High system operating pressures

Instrument used to measure the specific gravity of absorption Chillier solutions is the.

Hydrometer

If a cooling tower is equipped with tow or more cells,what can be done to ensure that the water flow to each cell is the same

Install a balancing valve to ensure that the water flow to each cell is the same

The flow through an orifice metering device

Is constant as long as the pressure drop across the orifice remains the same

The rate of the heat exchanger between two liquids

Is greater than the rate of heat exchange between two gases, as well as greater than the rate of heat exchange between a gas and a liquid

Which of the following is true regarding cooling tower fill

It should be kept wet at all times

When winterizing reciprocating compressor is restarted

It will start up on loaded until the oil pressure builds up

Which type of pump seal is typically used for pressures up to a maximum of 300 PSIG

Mechanical seal

On a close coupled pump,the impeller is

Mounted directly on the motor shaft

W variable frequency drive is used to vary

Number of cycles per second of the power supplied to the voltage

A diverting valve is manufactured with

One inlet ports, two outlet ports

It's a trickle compressor starts unloaded and only begins to load up after the motors up to speed, this is accomplished using

Pre-rotational guide vanes

Cassidy control mission trip compressor is accomplished by the

Prerotational guide vanes

The electronic expansion valve relies on

Pressure transducer's to maintain the desired, evaporator saturation pressure

Both spray, pond and natural draft cooling towers rely on _________ to move air through them

Prevailing winds

The compressor is equipped with the internal check valve to

Prevent backward, refrigerant flow in the system, compressor cycles off

The term "feet of head" is used to express

Pump capacity

Which of the following statements is true regarding pitted contactor and starter Contacts?

Putting a current electricity arcs as starter contacts open and close

Capacity control on an absorption system is typically accomplish by varying

Rate at which heat is supplied to the concentrator

In oil pump for a______ compressor is the driven from the actual compressor shaft

Reciprocating

Cooling towers require blowdown too

Reduce the concentration of minerals and other contaminants in the water tower

In auto transformer start is commonly referred to as

Reduce voltage start

Excessive buildup of minerals in the cooling water tower water can result in

Reduced heat transfer between the refrigerant and the condenser water

The purge unit is designed to

Remove air from a low-pressure chiller

If air is present in an absorption chilled water appliance, which of the following will most likely occur

Rust can form

Lithium Bromide (LiBr) is best characterized as a

Salt

Chilled water, when circulating throughout the building to provide comfort cooling, is referred to as

Secondary refrigerant

The capacity of a chiller operating with a rotary screw compressor is most likely controlled by a

Slide valve on the compressor suction side

The cooling tower component referred to as fill can be made of all of the following, except

Steel

The solution that leaves the concentrator in in absorption chiller is referred to as

Strong solution

Which type of pump seal is typically used at pressures to a maximum of 150 PSIG

Stuffing box

Two types of seals are typically found on pumps are the

Stuffing box and mechanical seal

Compressors that are cool with refrigerant that leaves evaporator are referred to as

Suction cooled compresses

If the compression ratio on a centrifugal compressor rises to high, the compressor will stop pumping and make a loud sound commonly referred to as

Surge

An adiabatic process is one that result in change in

Temperature and/or pressure but no change in heat Contant

Which of the following is true regarding a high-pressure chiller equipped with an Oarfish metering device

The chiller has critical refrigerant charge

Why is water not used as the primary refrigerant in a vapor compression refrigeration system?

The compressor would have to pump over 2400 feet of water vapor for each pound of water circulated through the system

Before starting up a chiller

The crank case heater must be energized for a period, typically 24 hours

In order for centrifugal pumps to operate properly

The eye of the impeller must be below the water level

What will occur if the strong solution and absorption chiller becomes too strong

The machine will stop cooling, and the solution will crystallize

In the cross flow cooling tower configuration

The water flows down in the air flows at a 90° angle to the water

In the counter, flow cooling tower configurations

The water flows down the air flows up

Which of the following statements is true regarding package type chillers

They require field installed waterlines

Oil pumps are used in conjunction with centrifugal compressor's typically use

Three phase ,fractional horsepower motors

Why is it sometimes required to open cooling towers to be equipped with tower wedding systems

To prevent algae and other biological contaminants growth

A mixing valve is manufactured with

Two inlet ports , one outlet port

The system component that illuminates the constant starting, and stopping of a cooling tower fan is the

Variable frequency drive

The outer portion or shell of the compressor used on a low-pressure chiller is called the

Volute

How are the seals on circulator pumps typically luberated

Water

Circulating water throughout the building to provide comfort cooling. Is it desirable from an economic standpoint because

Water is less expensive than refrigerant

The solution that is pumped into the concentrator in an absorption chillers, referred to as

Weak solution

Voretextign in a tower is best described as

Whirlpool action

How is a packing gland tightened

With a wrench

With a Y Delta or star Delta configuration the motor start as a

Wye configurations then transfers to a delta configuration

Galvanize steel does not readily rust because the Steelers coded with

Zinc

The strainer in a cooling tower is located

at the point where the water leaves the cooling tower

Using a hand operated valve to control cooling tower blowdown is

not a desirable or recommended option