Electricity unit 17 review

Changing of the compressor capacity to meet the cooling load in the conditioned space is an example of _____________________.

• Zone control

• Ambient control

• Capacity control

• Cooling anticipation

Commercial and industrial packaged units are commonly installed ___________________.

• Inside the structure

• On the roof

• On the ground

• On the wall

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 an advantage of using electronic control systems to control commercial and industrial air conditioning systems?

• Electronic controls operate on very low voltages

• Smaller components that are easier to work with

• Versatility to control variable speed or variable capacity loads

• All of the choices are correct

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 choices is an output device used on a direct digital control system?

• Outside air temperature sensor

• Return air damper control

• Return air temperature sensor

• 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