Two basic categories of chillers are the ____.

A benefit of operating a compressor unloaded is ____.

A reciprocating compressor with six cylinders, three banks of two cylinders each, can have its capacity reduced by unloading to ____% of full capacity.

Speeds up to ____ rpm are used in centrifugal compressors.

A centrifugal compressor uses ____ for capacity control.

The compressors used in low pressure chillers are the ____ type.

When a chiller using a low-pressure refrigerant is operating, the low pressure side of the system ____.

A purge unit ____.

To unload a reciprocating compressor, hot gas bypass across the cylinder is the best method.

When referring to evaporators, the terms "direct expansion" and "dry type" can be used interchangeably.

High pressure chillers use either air- or water-cooled condensers.

Thermostatic expansion valves are the only metering devices used in high pressure chillers.

Low pressure chillers use either air- or water-cooled condensers.

Lithium bromide is ideal for use in absorption systems because it is non-corrosive.

Electronic starters are much smaller than conventional starters.

A chiller typically cools ____________________ (what liquid?) for the purpose of air conditioning.

In centrifugal compressors, capacity control is accomplished by the use of __________________________________________ at the impeller inlet.

The pressure difference in a low-pressure chiller is produced by a(n) ____________________ compressor.

The device that automatically helps to remove non-condensables from a chiller is called a(n) ____________________.

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.

The refrigerant in an absorption chiller whose source of energy is steam or hot water is _____________________.

Two methods commonly used to unload a reciprocating compressor are:

Multiple smaller compressors are sometimes preferred over one large compressor because:

What is accomplished by having a compressor that is equipped with unloaders?

What is the reason to use cylinder unloading in high pressure chillers?

Since there are no "valves" in a scroll compressor, what must be done to prevent refrigerant from flowing backward when the compressor cycles off?

Centrifugal compressors are designed with the lubrication isolated from the refrigerant vapor. Why?

Explain the difference, with respect to superheat, between a dry type evaporator and a flooded evaporator.

The ends of a chiller evaporator are closed off by standard or marine boxes. What is the difference?

In a lithium bromide system, the refrigerant boils at 40°F. What is the corresponding absolute pressure required?

How is the capacity of a screw compressor controlled? (Unit 47 - High-Pressure, Low-Pressure, and Absorption Chilled-Water Systems) The capacity is controlled by a ________ that blocks off the inlets to the screw involutes.

If the blower on a cooling tower breaks down on a hot day, the ____.

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 ____.

Cooling towers are designed to reduce the entering water temperature to within ____°F of the air's wet-bulb.

When sizing a cooling tower, the tower is sized to handle the cooling load of the conditioned area plus about % for heat of compression.

Natural draft towers and spray ponds are designed to produce a difference in water and air temperatures of ____°F.

Two methods used to aid the evaporation rate of water in a forced or induced draft tower are ____.

A blowdown system for a cooling tower ____.

The purpose of the cooling tower bypass valve is to ____.

Two types of shaft seals used for centrifugal pumps are ____.

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.

A well-designed and installed cooling tower requires only a minimum of maintenance.

Distilled water is added to the cooling tower to make up for water lost during blowdown.

The condenser water pump is the device that moves the water through the condenser and cooling tower circuit.

If vortexing occurs, it is an indication that there is not enough air in the tower.

The difference between the entering air wet-bulb temperature and the temperature of the water leaving the tower is called the _____________________.

Natural draft cooling towers usually has an approach temperature of about _____________________°F because of relying only on the winds.

A spray pond would be an example of a(n) _____________________ draft cooling application.

Larger cooling towers generally use _____________________-type fans.

The two air flow patterns for cooling towers are _____________________ and counterflow.

____________________ allow the motor to soft start and to coast down without abruptly shutting the motor off.

Condenser water pumps are normally ____________________ pumps.

Drift is defined as:

The water that leaves a cooling tower passes through a strainer to:

What prevents the water in a cooling tower from freezing in cold weather?

Describe vortexing.

Define angular alignment.

Define parallel alignment.

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

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

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

Reciprocating chillers have crankcase heaters to ____.

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

Water-cooled chillers must have water treatment to ____.

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

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

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

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

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

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

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.

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

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

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

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

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.

To remove particles that may be in suspension and circulating in a water circuit, a(n) ____________________ is used.

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.

There are three lines of defense against refrigerant leaks in a service valve: the back seat, the packing gland, and the ____________________.

If an absorption unit is started with very cold water in the cooling tower, the lithium bromide in the unit may _________________.

Before allowing the compressors of a water-cooled chiller to start up, what two things must be done?

Reciprocating, scroll and rotary compressors are lubricated by:

After being cleaned, the condenser tubes may be checked for stress cracks, erosion, wear on the outside and other defects, by means of what type of instrument?

Package units are factory-assembled, factory-charged, self-contained systems that have all of the major system components contained in a single housing.

The rooftop unit houses the fans and blowers that move air through the heating and cooling portions of the unit but not through the condenser.

Although packaged air-conditioning equipment comes precharged with refrigerant and no field piping must be done, the installation of a rooftop package unit involves many steps and can be very dangerous.

Improper clearances do not affect the ability of service personnel to perform their jobs adequately.

Some roofs are bonded, which are roofs that carry a written warranty or insurance policy that protects the building owner in the event damage from leaks occurs.

Curbs can be prefabricated, but many larger curbs are shipped unassembled.

Gasketing materials and foam panels that are shipped with the curb are not part of the curb and should be discarded.

By raising the forearm in the air, index finger pointing upward and holding the hands straight, the operator will know to raise the cable on the crane.

The term enthalpy refers to the total heat content in the air, which accounts for both the temperature and the moisture content of the air.

By utilizing a strategy called demand control ventilation, DCV, the amount of outside air being brought into the building can be varied based on the actual occupancy level in the structure.

In order to deliver different volumes of air to various areas in an occupied space, the blowers used on VAV systems must be able to modulate their openings to accommodate the changing needs of the system.

The unit’s location should be carefully selected so the system’s operation is not adversely affected by air being able to ____ the condenser coil.

It is good field practice to double-check and possibly triple-check the ____ decision, since the cost of repairing an improperly cut roof can be very high.

If the curb is mounted as part of a new construction process, it can be assembled and installed as soon as the ____ support system is in place.

____ are intended to help provide the correct amount of ventilation and also help reduce cooling costs by allowing outside air to be introduced to the conditioned space when conditions are correct.

The economizer is able to increase or decrease the amount of outside air that is brought into the structure with two ____.

An enthalpy sensor includes solid state temperature and ____ sensors.

When multiple rooftop units are used to condition the air in a building, it is common practice to label the units and their corresponding _____________________.

Many rooftop package units are equipped with multiple _____________________ fans.

A frame that is used to mount HVAC equipment is called a(n) _____________________.

The water coil in a dry cooler can contain 100% water or can be a mix of water with _____________________.

The temperature sensor used in chilled-water VAV systems to detect when the outside air is cold enough to cause freezing, is typically called a(n) _____________________.

Name the four common types of VAV boxes.

What are some drawbacks of adding more antifreeze than needed to prevent freezing in the chilled water piping system?

Free cooling refers to: