Unlock document.
This document is partially blurred.
Unlock all pages and 1 million more documents.
Get Access
306)
306)
The current relay is wired with the:
A)
Relay coil in parallel with the run winding and the contacts wired in series with the start
winding.
B)
Relay coil in parallel with the start winding and the contacts wired in series with the run
winding.
C)
Relay coil in series with the run winding and the contacts wired in series with the start
winding.
D)
Relay coil in series with the start winding and the contacts wired in series with the run
winding.
Answer:
C
Explanation:
A)
B)
C)
D)
307)
307)
Which of the following is NOT a standard mounting dimension for an electric motor?
A)
Motor circumference
B)
Shaft diameter
C)
Shaft centerline to base distance
D)
Mounting hold spacing
Answer:
A
Explanation:
A)
B)
C)
D)
308)
308)
This symbol represents:
A)
Heating thermostat.
B)
Cooling thermostat.
C)
Close-on-rise pressure switch.
D)
Open-on-rise pressure switch.
Answer:
B
Explanation:
A)
B)
C)
D)
81
309)
309)
This symbol represents:
A)
Heating thermostat.
B)
Cooling thermostat.
C)
Close-on-rise pressure switch.
D)
Open-on-rise pressure switch.
Answer:
D
Explanation:
A)
B)
C)
D)
310)
310)
What is the purpose of the legend on HVACR electrical diagrams?
A)
To provide a reference list of the circuits used in the diagram
B)
To show all the product variations and trace the history of that model
C)
To list the symbols used in the diagram and define their use
D)
To provide the operational sequence for the unit
Answer:
C
Explanation:
A)
B)
C)
D)
311)
311)
This symbol represents:
A)
Heater.
B)
Light.
C)
Transformer.
D)
Motor.
Answer:
B
Explanation:
A)
B)
C)
D)
82
312)
312)
A normally closed set of relay contacts will close when:
A)
Power is not applied to the relay coil.
B)
Power is applied to the contacts.
C)
Power is applied to the relay coil.
D)
Power is not applied to the contacts.
Answer:
A
Explanation:
A)
B)
C)
D)
313)
313)
This symbol represents:
A)
Transformer.
B)
Single-phase motor.
C)
Compressor with internal overload.
D)
Three-phase motor.
Answer:
D
Explanation:
A)
B)
C)
D)
314)
314)
A technician looking for the 24 V coil of a contactor in a ladder diagram would find it in which
power section?
A)
High-voltage
B)
Transformer
C)
Low-voltage
D)
Compressor
Answer:
C
Explanation:
A)
B)
C)
D)
315)
315)
What do the rungs of a ladder diagram represent?
A)
Actual system wires
B)
Individual controls
C)
Individual loads
D)
Individual electrical circuits
Answer:
D
Explanation:
A)
B)
C)
D)
83
316)
316)
Types of control systems include:
A)
Line voltage, low voltage, and communicating.
B)
Voltage, current, and milliamp.
C)
Pneumatic, hydraulic, and electro-mechanical.
D)
Pneumatic, electromechanical, electronic, and DDC.
Answer:
D
Explanation:
A)
B)
C)
D)
317)
317)
An open-loop system:
A)
Monitors conditions that it can control.
B)
Monitors conditions that it cannot control.
C)
Controls conditions for machines that are open to the air.
D)
Connects to the main controller through an open wireless system.
Answer:
B
Explanation:
A)
B)
C)
D)
318)
318)
A control malfunction that results from a system heating or cooling past its setpoint is called:
A)
Lag.
B)
Overshoot.
C)
Temperature swing.
D)
Anticipation.
Answer:
B
Explanation:
A)
B)
C)
D)
319)
319)
Electronic control systems operate by:
A)
Processing electronic signals with a microprocessor.
B)
Providing a modulating air pressure in response to monitored conditions.
C)
Turning relay coils on or off to complete circuits.
D)
Providing a varying DC voltage in response to monitored conditions.
Answer:
D
Explanation:
A)
B)
C)
D)
84
320)
320)
What are proportional controls?
A)
Proportional controls integrate the signals from several sensors and control the system
operation based on the proportion of sensors requiring conditioning.
B)
Proportional controls regulate the starting and stopping of the system to keep the run time
ratio as low as possible.
C)
Proportional controls have the ability to measure the controlled variable and the system
output and dynamically adjust the setpoint to achieve more precise control.
D)
Proportional controls increase or decrease the output of a controlled device in proportion to
the level of the measured condition.
Answer:
D
Explanation:
A)
B)
C)
D)
321)
321)
Electro-mechanical control systems operate by:
A)
Providing a varying DC voltage in response to monitored conditions.
B)
Turning relay coils on or off to complete circuits.
C)
Providing a modulating air pressure in response to monitored conditions.
D)
Processing electronic signals with a microprocessor.
Answer:
B
Explanation:
A)
B)
C)
D)
322)
322)
A closed-loop system:
A)
Connects to the main controller through an enclosed conduit.
B)
Controls conditions for machines that are not open to the air.
C)
Monitors conditions that it can control.
D)
Monitors conditions that it can not control.
Answer:
C
Explanation:
A)
B)
C)
D)
85
323)
323)
The system ________ can communicate with each other and adjust system operation to match the
heat load and operating conditions.
A)
computers
B)
controls
C)
remotes
D)
components
Answer:
D
Explanation:
A)
B)
C)
D)
324)
324)
A unit's communicating status can be determined by:
A)
Checking the amp draw of the communicating bus.
B)
Ohming the communication lines.
C)
Checking the voltage on the communicating bus.
D)
Checking the communicating LED on the board.
Answer:
D
Explanation:
A)
B)
C)
D)
325)
325)
The availability of "standard" communicating components and an open protocol means that more
manufacturers can use communicating controls, opening the market up. This was demonstrated at
the 1996 ASHRAE show in Atlanta, when multiple controllers from several major manufacturers
were up and operating, all connected to the same ________ system.
A)
standard protocol
B)
ClimateTalk
C)
BACnet
D)
climate
Answer:
C
Explanation:
A)
B)
C)
D)
326)
326)
A relay control system requires:
A)
A wire for each system function.
B)
A separate control board for each relay on the system.
C)
A communication bus for all the relay operation.
D)
Adjustable relays, which can compensate for voltage drop in the control signals.
Answer:
A
Explanation:
A)
B)
C)
D)
86
327)
327)
Each component in a communicating control system must have its own:
A)
Power supply.
B)
24 V relay.
C)
Microprocessor.
D)
Transformer.
Answer:
C
Explanation:
A)
B)
C)
D)
328)
328)
To access the Lennox Installer menu, press the ________ in the bottom right corner of the screen
for five seconds.
A)
menu button
B)
advanced button
C)
installation button
D)
Lennox logo
Answer:
D
Explanation:
A)
B)
C)
D)
329)
329)
Communicating systems can communicate with devices and networks outside the HVACR
network using:
A)
Power line communication technology.
B)
Satellite uplinks.
C)
Special dedicated communication wiring to the outside network.
D)
Internet.
Answer:
D
Explanation:
A)
B)
C)
D)
330)
330)
In a basic electric circuit with a fixed resistance, when voltage increases:
A)
Current remains the same.
B)
Current increases.
C)
Current decreases.
D)
The voltage has no effect on the current in an electric circuit.
Answer:
B
Explanation:
A)
B)
C)
D)
87
331)
331)
In an electrical circuit, amps are:
A)
One coulomb of electrons flowing in one second.
B)
Opposition to the flow of electricity.
C)
The ability to make current flow.
D)
The ability of electricity to do work.
Answer:
A
Explanation:
A)
B)
C)
D)
332)
332)
In a basic electric circuit with a fixed resistance, when voltage decreases:
A)
Current remains the same.
B)
Current increases.
C)
Current decreases.
D)
The voltage has no effect on the current in an electric circuit.
Answer:
C
Explanation:
A)
B)
C)
D)
333)
333)
In a basic electric circuit with a steady potential, when resistance increases:
A)
Current decreases.
B)
Current remains the same.
C)
Current increases.
D)
The resistance has no effect on the current in an electric circuit.
Answer:
A
Explanation:
A)
B)
C)
D)
334)
334)
Electrical potential is:
A)
One coulomb of electrons flowing in one second.
B)
Opposition to the flow of electricity.
C)
The ability to make current flow.
D)
The ability of electricity to do work.
Answer:
C
Explanation:
A)
B)
C)
D)
88
335)
335)
When a line-duty overload protecting a heater detects an overload, it:
A)
Breaks the line voltage to the heater.
B)
Cuts power to a relay which powers the heater.
C)
Breaks the power line to the house.
D)
Breaks the heater.
Answer:
A
Explanation:
A)
B)
C)
D)
336)
336)
A protective device that prevents the operation of a unit when there is inadequate fluid flow is
called a:
A)
Kinetic energy transducer.
B)
Float switch.
C)
Fluid level switch.
D)
Sail switch.
Answer:
D
Explanation:
A)
B)
C)
D)
337)
337)
The fourth color band represents:
A)
The first two digits of the resistor value.
B)
The multiplier for the resistor valve.
C)
The resistor tolerance.
D)
The color frequencies of the waveform.
Answer:
C
Explanation:
A)
B)
C)
D)
338)
338)
When replacing a fuse you must match the:
A)
Volt, amp, instantaneous current, and physical size.
B)
Amp rating.
C)
Volt and amp rating.
D)
Volt, amp, and instantaneous current rating.
Answer:
A
Explanation:
A)
B)
C)
D)
89
339)
339)
Mica and disc capacitors are used on:
A)
Motor circuits.
B)
Electronic circuit boards.
C)
Power transmission lines.
D)
Heavy-duty power supplies.
Answer:
B
Explanation:
A)
B)
C)
D)
340)
340)
ECM motor speed is controlled by:
A)
Pulses of DC power sent by the control module to the windings.
B)
Which speed winding is connected.
C)
The voltage applied to the motor.
D)
The frequency and the number of poles.
Answer:
A
Explanation:
A)
B)
C)
D)
341)
341)
A major difference between three-phase motors and single-phase motors is that:
A)
Three-phase motors use three sets of starting components.
B)
Three-phase motors do not need any type of starting components.
C)
Three-phase motors use three times as much current.
D)
Three-phase motors have a laminated iron rotor.
Answer:
B
Explanation:
A)
B)
C)
D)
342)
342)
A technician has installed a new three-phase motor, but it is running in reverse. What should she
do to correct the rotation?
A)
Reverse the capacitor leads.
B)
Check the schematic diagram.
C)
Replace the motor.
D)
Reverse two motor power supply leads.
Answer:
D
Explanation:
A)
B)
C)
D)
90
343)
343)
The part of an AC induction motor that induces the current flow in the rotor is called:
A)
The armature.
B)
The rotor.
C)
The stator.
D)
The field.
Answer:
C
Explanation:
A)
B)
C)
D)
344)
344)
The phase current of a wye-wound three-phase motor is:
A)
3 times the line current.
B)
1.5 times the line current.
C)
1.73 times the line current.
D)
Equal to the line current.
Answer:
D
Explanation:
A)
B)
C)
D)
345)
345)
Which organizations specify standards for electric motors? More than one response required.
A)
Air-conditioning Heating Refrigeration Institute (AHRI)
B)
American Society Heating Refrigeration Air-conditioning Engineers [ASHRAE]
C)
National Electrical Manufacturers Association (NEMA)
D)
International Electrotechnical Commission (IEC)
Answer:
C, D
Explanation:
A)
B)
C)
D)
346)
346)
A megohmmeter can detect:
A)
Moisture.
B)
Insulation faults.
C)
Contamination.
D)
All of these.
Answer:
D
Explanation:
A)
B)
C)
D)
91
347)
347)
Grounded windings can be detected by measuring the resistance with a multimeter between:
A)
The start winding and common terminal.
B)
The run winding and common terminal.
C)
The windings and the motor frame.
D)
The start winding and run winding.
Answer:
C
Explanation:
A)
B)
C)
D)
348)
348)
The best way to diagnose an ECM motor is to:
A)
Turn off power to the unit, remove the control module, and ohm test the motor.
B)
Leave power on to the unit and check for voltages at the harness.
C)
Turn off power to the unit, remove the control harness, and connect a test controller.
D)
Turn off power to the unit, remove the control harness, and ohm test the lead end to end.
Answer:
C
Explanation:
A)
B)
C)
D)
92
349)
349)
Where does the other end of the orange wire on the contactor terminal L2 connect?
A)
To the indoor fan capacitor
B)
To T2 on the contactor
C)
To the primary side of the transformer
D)
To L1 on the contactor
Answer:
C
Explanation:
A)
B)
C)
D)
93
350)
350)
This symbol represents:
A)
Heater.
B)
Light.
C)
Transformer.
D)
Motor.
Answer:
A
Explanation:
A)
B)
C)
D)
351)
351)
Which diagram types are most useful for understanding the operating sequence of the unit?
A)
Ladder
B)
Schematic
C)
Component location
D)
Pictorial
Answer:
A
Explanation:
A)
B)
C)
D)
352)
352)
What type of electrical device is a relay?
A)
A control
B)
A load
C)
A combination load and control
D)
A relay is not an electrical device.
Answer:
C
Explanation:
A)
B)
C)
D)
353)
353)
A heat pump condenser contains this unique control device, which switches the flow of
refrigerant depending on heating or cooling mode.
A)
Reversing valve
B)
Bypass solenoid
C)
Flow switch
D)
Liquid line solenoid valve
Answer:
A
Explanation:
A)
B)
C)
D)
94
354)
354)
What are two-position controls?
A)
Two-position controls simply stop and start devices to maintain the desired condition.
B)
Two-position controls can be mounted either horizontally or vertically and still operate
correctly.
C)
Two-position controls incorporate a normal operating setting and an energy-saving
economy mode.
D)
Two-position controls will work correctly on either side of the electrical circuit.
Answer:
A
Explanation:
A)
B)
C)
D)
355)
355)
A switch controls the flow of electricity by:
A)
Adding resistance to the circuit when it is turned off.
B)
Breaking the circuit when it is turned off.
C)
Modulating the current to a low level when it is turned off.
D)
Using up all the electricity when it is turned off.
Answer:
B
Explanation:
A)
B)
C)
D)
356)
356)
How should a thermostat be connected to a system that has two transformers: one in the furnace
and one in the air conditioner?
A)
Wire both transformers to the R terminal.
B)
Wire the furnace to RC and the air conditioner to RH.
C)
Tie the transformers together and leave off the R terminal.
D)
Wire the furnace to RH and the air conditioner to RC.
Answer:
D
Explanation:
A)
B)
C)
D)
95
357)
357)
In a communicating system, control signals and information are exchanged:
A)
Only when permission is granted by the operator.
B)
In both directions between the components and the communicating control.
C)
In one direction: from all the system components back to the communicating control.
D)
In one direction: from the master controller to all the components.
Answer:
B
Explanation:
A)
B)
C)
D)
358)
358)
Why are communicating systems increasing in popularity?
A)
They can be used to replace a land-line telephone system.
B)
They improve system efficiency and convenience.
C)
They raise the cost of equipment and increase service calls.
D)
They can serve as a router for a wireless home entertainment system.
Answer:
B
Explanation:
A)
B)
C)
D)
359)
359)
A big reason that communicating systems improve efficiency is:
A)
They monitor and correct power factor.
B)
Relays consume large amounts of power in conventional systems.
C)
They can make intelligent decisions based on actual operating conditions.
D)
They switch faster than relay systems.
Answer:
C
Explanation:
A)
B)
C)
D)
360)
360)
The first two color bands represent:
A)
The first two digits of the resistor value.
B)
The multiplier for the resistor value.
C)
The resistor tolerance.
D)
The color frequencies of the waveform.
Answer:
A
Explanation:
A)
B)
C)
D)
96
361)
361)
What is the instantaneous rating of a fuse?
A)
A rating of the maximum current that the fuse can safely interrupt
B)
The nominal amp rating × 1.25
C)
The nominal amp rating + 1
D)
The fuse nominal amp rating
Answer:
A
Explanation:
A)
B)
C)
D)
362)
362)
The different colors used for the color bands on resistors represent:
A)
Numbers.
B)
Frequencies.
C)
Letters.
D)
Letters and numbers.
Answer:
A
Explanation:
A)
B)
C)
D)
363)
363)
Electrical insulation is classified by the ________ stability of the materials that are used for the
winding.
A)
voltage
B)
pressure
C)
current
D)
temperature
Answer:
D
Explanation:
A)
B)
C)
D)
364)
364)
Which types of electrical diagrams show all the electrical components as they appear in the unit?
A)
Component location diagram and pictorial diagram
B)
Installation diagrams
C)
Ladder diagram and schematic diagram
D)
Factual diagram and field connection diagram
Answer:
A
Explanation:
A)
B)
C)
D)
97
365)
365)
Ladder diagrams show a system's sequence of operation:
A)
From left to right. Actions on the left occur before actions on the right.
B)
By the order of the circuits. The circuit at the top of the diagram is energized first, and the
circuit at the bottom is energized last.
C)
By showing the loads and switches in each circuit.
D)
By showing each physical wire on the unit.
Answer:
C
Explanation:
A)
B)
C)
D)
366)
366)
What does the term "interoperability" mean?
A)
The air-conditioning control system will function using either iOS or Android.
B)
The air conditioner and furnace can operate at the same time.
C)
An evaporator coil from one manufacturer can be connected to a condensing unit from
another manufacturer.
D)
Components from different manufacturers can function properly in the same system.
Answer:
D
Explanation:
A)
B)
C)
D)
367)
367)
A communicating control system can be compared to a:
A)
Telephone network.
B)
Computer network.
C)
Social network.
D)
Relay network.
Answer:
B
Explanation:
A)
B)
C)
D)
368)
368)
Compared to motor capacitors, paper and film capacitors are:
A)
Larger in rating but smaller in physical size.
B)
Smaller in rating and physical size.
C)
Larger in rating and in physical size.
D)
Smaller in rating but larger in physical size.
Answer:
B
Explanation:
A)
B)
C)
D)
98
369)
369)
Controls that use human hair for sensing are:
A)
Thermostats.
B)
Current overloads.
C)
Pressurestats.
D)
Humidistats.
Answer:
D
Explanation:
A)
B)
C)
D)
370)
370)
This symbol represents:
A)
Heater.
B)
Light.
C)
Transformer.
D)
Motor.
Answer:
C
Explanation:
A)
B)
C)
D)
371)
371)
What do the rungs on a ladder diagram represent?
A)
The circuit loads
B)
The line voltage power
C)
The individual circuits
D)
The rungs on each ladder diagram stand for something different.
Answer:
C
Explanation:
A)
B)
C)
D)
99
