Chapter 17 review questions

A commercial and industrial conditioned air system using water as the heat transfer medium will require a _________________________________.

• Hot water boiler and hot water pump

• Water chiller and chilled water pump

• Hot water boiler, water chiller, and hot and chilled water pumps

• Hot water and chilled water pumps

Commercial and industrial packaged units are commonly installed ___________________.

• Inside the structure

• On the roof

• On the ground

• On the wall

Commercial condensing units with multiple condenser fans will often cycle some of the fans off during cool ambient temperatures to maintain a condensing temperature at or around _________________.

• 50ºF

• 75ºF

• 90ºF

• 120ºF

Compressor capacity control that involves making cylinders inactive by controlling the valves using solenoids is an example of _____________________.

• Cylinder unloading

• Valve lifting

• Speed variation

• Modular compression

How long will the average anti-short-cycling time delay will cause the unit to delay before restarting?

• Two minutes

• Five minutes

• Ten minutes

• One hour

What circulates the hot water in hot water heating system?

• Hot water boiler

• Hot water coil

• Hot water pump

• Hot water zone controller

What is the purpose of an interlock in a control system?

• To start the compressor and condenser fan motor at same time

• To make certain that the condenser fan motor and water-cooled condenser are operating

• To make certain that a major load does not attempt to operate without a necessary load operating

• To make certain that the indoor blower is not operating without compressor operation

What is used to cool water that is supplied to chilled water coils used in commercial systems?

• Water chillers

• Evaporative coolers

• Water coolers

• Direct-expansion cooler

Which of the following controlling elements could be used as inputs for a direct digital control system?

• Supply air temperature, supply air control damper, return air temperature, and return air damper control.

• Supply air temperature, supply air control damper, outside air temperature, and outside control damper

• Supply air temperature, return air temperature, outside air temperature, and mixed air temperature

• Outside air temperature, outside air damper, mixed air temperature, and enthalpy control

Which of the following electrical components would be used as safety controls on commercial condensing units?

• Low pressure switch

• High pressure switch

• Compressor motor overloads

• All of the controls would be used as safety controls