Deck 17: Commercial and Industrial Air 252dconditioning Control Systems

Question 1

The ____________________ packaged unit is built in one unit, much like the air-cooled packaged unit with a remote condenser, except that the condenser is also mounted with the unit.

Answer 1

water-cooled

Question 2

What two methods are used to start three-phase compressors on large systems?

Answer 2

There are two methods used to start three-phase compressors on large systems: part winding and across-the-line.

Question 3

Many commercial and industrial complexes use a(n) ____________________ to heat water that is supplied to heat transfer devices that condition the air in a structure or zone.

Answer 3

hot water boiler

Question 4

The pressure switch is used to start the compressor on most systems.

Question 5

What are the different sections of multi-zone roof top units?

Question 6

Most large commercial and industrial conditioned air systems use large ____________________ to supply the air flow that is needed to condition the structure.

Question 7

____________________ is the method that is used to vary the capacity of the compressor as the load increases and decreases.

Question 8

How are elements represented in the direct digital control process?

Question 9

Commercial and industrial air-cooled packaged units can be mounted on the outside of a structure on ground level and through an air delivery system supplying conditioned air to the structure.

Question 10

The ____________________ system uses air to transmit the signal from the sensor to the controller and on to the controlled device.

Question 11

An across-the-line type of motor starting requires several contactors.

Question 12

The multi-zone roof top units are usually custom manufactured for a specific application with a specific number of zones.

Question 13

Low voltage (24 volts) will not effectively energize some of the large control components that are used in larger systems; therefore, line voltage control systems are used.

Question 14

Why do water-cooled condensing units require an interlock in the condensing unit control circuit?

Question 15

Almost all control systems use a(n) ____________________ to control the temperature within a given structure, space, or zone.

Question 16

What did early commercial and industrial control systems use to maintain the temperature in a structure, zone, or room?

Question 17

In pneumatic control systems, the ____________________ is the device that senses the desired temperatures and relays them to the controller by supplying specific air pressures representing a specific temperature.

Question 18

Some commercial and industrial systems use ____________________ to cool water and supply it to chilled water coils in the air flow.

Question 19

Direct digital control uses a(n) ____________________, which acts as a digital controller.

Question 20

Water chillers require a(n) ____________________ in the chiller control circuit to ensure that the chilled water pump is operating before the water chiller refrigeration unit operates.