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WorksheetsIDA-101 Baseline Test
Total questions: 100
Worksheet time: 50mins
One of the most important things for a technician to remember when dealing with electrical circuits is to _______________ them.
Avoid
Disconnect
Respect
De-energize
Which of the following can occur when electrical current flows through the human body?
Death
Serious injury
Experience a stinging sensation
All the choices are possible
A person will experience electric shock if their body becomes part of an electrical circuit by making contact with the ____________________.
L1 and L2 conductors in a disconnect switch
All of the choices will result in electrical shock
L1 and neutral conductors on a furnace
L2 and grounding conductors on a condensing unit
Which of the following paths of electrical current flow through the body has the highest risk of causing severe injury or death?
From the left hand to the left elbow
From the right hand to the left hand
From the right knee to the right foot
From the thumb to the index finger on the right hand
Which of the following choices is a potential hazard technicians face when working with electricity?
Electrical shock
Fire
All of the choices are correct
Arc flash and burns
How often is the National Electrical Code revised?
Every five years
Every eight years
Every four years
Every year
Which article in the National Electrical Code specifically covers air conditioning and refrigeration equipment?
Article 400
Article 440
Article 540
Article 300
The National Electrical Code is published by the __________________________.
National Fire Protection Association
National Electrical Code Council
American Electricity Safety Association
U.S. Department of Energy
What should a technician do if they need to plug a grounded metal drill with a three-prong plug into an older receptacle made for two-prong plugs?
Tell the customer the work cannot be completed
Break off the third (ground) prong so the plug will fit the receptacle
Purchase a portable generator to power the drill
Use a grounding adapter to connect the drill to the receptacle
Which of the following electrical devices is designed to protect electrical circuits from excessive current flow?
Ground fault circuit interrupters and circuit breakers
Fuses and circuit breakers
Arc fault circuit interrupters and ground fault circuit interrupters
Thermal overloads and fuses
Arc flash circuit interrupters are electrical devices designed to protect structures from fires started by electrical arcs caused by __________________________.
Frayed wiring
Loose wiring connections
Faulty or damaged electrical equipment
All of the choices are correct
Most electrical circuits shown in a schematic diagram are arranged ____________________________.
To show component placement in the equipment
In order from the circuit with highest current draw to the lowest current draw
With loads in alphabetical order
With the circuits between the lines representing the electrical source
The following electrical symbol represents a ____________.
Shaded-pole compressor
Single-phase compressor
Dual-phase compressor
Three-phase compressor
The following electrical symbol represents a ____________.
Relay coil
Circuit breaker
Fuse
Signal light
The following electrical symbol represents a ____________.
Motor winding
Defrost heater
Crankcase heater
Solenoid
What is the most common voltage used in residential low-voltage control systems?
24 volts
36 volts
48 volts
12 volts
The following schematic diagram of a dehumidifier shows a(n) _______________ control system.
Line-voltage
Low-voltage
Intermediate-voltage
Indirect-voltage
The defrost timer of the typical walk-in cooler will initiate defrost cycles ______________________.
When frost is detected on the evaporator
After every six hours of cooling operation
Every eight hours
At preset time intervals
Which of the following statements is true about the operation of the commercial freezer using the following schematic diagram?
All of the statements are true
The condenser fan motor operates when the compressor is operating
The defrost heater operates when the defrost timer is closed between terminals 4 and 2, and the defrost thermostat is closed
The compressor does not operate when the defrost heater is operating
What is the purpose of a limit switch on a gas furnace?
A safety device to turn off the gas valve if the temperature of the furnace’s heat exchanger reaches an unsafe level
A safety device to prevent the furnace from heating the structure above the set-point of the heating thermostat
A safety device to prevent the blower motor from overheating
A control device to turn the furnace on when the room temperature falls below the set-point of the limit switch
Which of the following statements is true about the operation of a packaged air conditioning unit if the fan switch on the thermostat is in the “on” position?
The indoor fan motor will cycle on and off with the compressor
The outdoor fan motor will operate continuously
The indoor and outdoor fan motors will operate continuously
The indoor fan motor will operate continuously
What is often used to control large contactors with high-voltage coils in commercial equipment that is controlled by a low-voltage thermostat?
Control relays
Lockout relays
Step-up transformers
Intermediate-voltage contactors
Which of the following statements is true about the lockout relay circuit shown in the following schematic diagram?
All of the statements are true about the lockout relay (LR) circuit
The lockout relay (LR) coil is wired in series with the contactor (C) coil
The contactor (C) coil will be de-energized when the lockout relay (LR) coil is energized
The lockout relay (LR) coil is wired parallel to the safety switches
A commercial air conditioning system that has two cooling capacities made possible by two compressors will likely be controlled by ______________________.
A multistage thermostat
A single-stage thermostat
A manual switch
A variable speed drive
Which terminal on a multistage thermostat operates the second-stage heating cycle?
W1
Y2
W2
Rh
When is the Y1 terminal energized on a multistage heating and cooling thermostat?
First-stage heating
First-stage cooling
Y1 is always energized
Second-stage heating
A heat pump can no longer supply enough heat to properly condition the structure without supplementary heating when operating below the ________________.
Balance point
Critical temperature
Thermal threshold
Equilibrium level
Which thermostat terminal will control the reversing valve for a heat pump system that energizes the reversing valve in the cooling mode of operation?
O
B
Re
W2
What happens during the defrost cycle on a typical heat pump system?
The supplementary heating is turned on
All of the actions occur during the defrost cycle
The outdoor fan motor is turned off
The reversing valve is put in the cooling mode
The voltage and amperage of alternating current electricity is represented graphically by a(n) __________________.
Sine wave
Square wave
Triangle wave
Sawtooth wave
How many alterations or current flow reversals are there in one cycle of alternating current electricity?
Two
Five
Three
One
What will be the approximate effective voltage of an alternating current voltage source if the peak voltage is 340?
240 volts
277 volts
360 volts
208 volts
The number of alternating currents in a circuit that are alternating at different time intervals describes the ___________ of the circuit.
Frequency
Power factor
Phase
Reactance
An electrical device that is composed of windings and a rotating magnet that is used to produce alternating current electricity is called a(n) _______________.
Rectifier
Alternator
Inverter
Generator
The sine waves representing each phase of three-phase alternating current electricity are separated by ___________ degrees.
120
90
180
360
When a conductor is exposed to fluctuating magnetic strengths or more than one magnetic field at a time, the voltage produced that counteracts the original voltage is caused by _______________.
Reactance
Conductance
Impedance
Inductance
What type of load resists changes to voltage more than changes in current flow when connected to alternating current electricity?
Conductors
Capacitors
Inductors
Resistors
What voltage will a technician read between L1 and neutral on a typical residential voltage system?
208 volts
120 volts
Zero volts
240 volts
What color wire is typically used for neutral conductors in a 120-volt circuit?
Black
Bare copper
White
Green
What voltage will a technician read between the L1 and L2 conductors on a typical residential voltage system?
240 volts
120 volts
208 volts
277 volts
What is an advantage of three-phase power over single-phase power?
All of these are advantages of three-phase power distribution systems
Three-phase motors have better starting and running characteristics than single-phase motors
Commercial customers can often buy three-phase power at a lower cost than single-phase power
Three-phase motors do not require special starting components such as capacitors and starting relays
Which of the following applications will not have a three-phase power distribution system?
Residential homes
Industrial buildings
Commercial buildings
Large institutional buildings
Which of the following choices best represents the measurements a technician will likely read on a three-phase, 240-volt delta system?
208 volts between all of the hot legs, 120 volts between two of the hot legs and ground, and 240 volts between the high leg and ground
240 volts between all of the hot legs, 120 volts between two of the hot legs and ground, and 208 volts between the high leg and ground
240 volts between all of the hot legs, 120 volts between two of the hot legs and ground, and 277 volts between the high leg and ground
120 volts between all of the three hot legs and volts between each hot leg and the ground
Which of the following three-phase voltage systems is useful for applications where there is a need for many 240-volt circuits, but very few 120-volt circuits?
240-volt delta system
208-volt wye system
277-volt wye system
230-volt wye system
What type of three-phase voltage system is commonly used in commercial and industrial applications to supply power to 277-volt single-phase loads?
575-volt wye systems
240-volt delta systems
277-volt wye systems
480-volt wye systems
A contactor will contain which of the following parts?
Coil
Contactors contain all of these parts
Armature
Contact
What part of a contactor slides up and down within slots within the contactor’s frame?
Mechanical linkage
Armature
Contacts
Coil
Contactor coils are available for which of the following voltages?
120 volts
24 volts
208/240 volts
Coils are available for all the voltages
Contact points in a contactor are often made of _____________________.
Brass alloy
Copper
Aluminum
Silver
Which of the following resistance readings indicates a shorted coil that could cause damage to the control system if energized?
Zero ohms
15 ohms
Infinite ohms
100 ohms
Which of the following contactor parts could develop faults and prevent proper operation?
Contacts
All parts could become faulty
Mechanical linkage
Coil
What would a reading of 15 volts across the contacts of the same pole of a contactor indicate?
15 volts is being supplied to the contactor
15 volts is being lost through the contact
15 volts is being supplied to the equipment
Voltage readings across the contacts are irrelevant
Relays are built with the same general components as ___________________.
Solenoids
Motors
Contactors
Transformers
Contactors are typically used to control high current applications and relays are used to control ________________ current applications.
Higher
All
Lower
Unlimited
An electric device that protects a load from high amperage draw by opening a set of contacts to break the circuit to the load describes a(n) _______________.
Solenoid
Current relay
Contactor
Overload
What overload protection device is composed of a piece of wire that melts if the current draw gets too high?
Thermal overload
Circuit breaker
Fuse
Magnetic overload
What does a line break overload do to protect a motor in an overload situation?
Cause the fuse to blow
Reduce the speed of the motor
Break the power to the motor
Break the power to the motor control circuit
The internal compressor overload used on most residential central systems is a ____________ type of overload.
Line break
Solid state
Pilot duty
Magnetic
What type of overload breaks the control circuit in an overload event?
Internal compressor overload
Circuit breaker
Thermal line-break overload
Pilot duty overload
Which of the following types of overload relays are used on magnetic starters?
Thermal relay
Molten-alloy relay
Bimetal relay
All these overload types are used
Which of the following conditions could prevent the contacts on a magnetic starter from closing?
Open control coil
Tripped overload relay
All these conditions will keep the contacts from closing
Worn or broken linkage
Motors are very important loads in heating, cooling, and refrigeration equipment because they are used to rotate ____________________.
All of the choices are correct
Fans
Pumps
Compressors
In which of the following areas do contactors and relays experience problems?
Failure of the mechanical linkage
Failures can be experienced in all these areas
Contact failure
Coil failure
If the voltage loss measured across the contacts of a contactor is more than 5% of the line voltage, the contactor ____________________.
Is too large for the application
Should be replaced
Is good
Has a faulty coil
What is the condition of a relay coil rated to operate on 24 volts if the coil has a resistance of 50 ohms?
Open
Good
Shorted
Grounded
What is the condition of a contactor coil rated to operate on 120 volts if the coil has a resistance of infinite ohms?
Open
Good
Shorted
Grounded
A problem with the mechanical linkage of a contactor could cause ____________________.
All of the choices are correct
Misalignment of the contacts
The contacts to stick closed
The contacts to not close
The contacts to open prematurely
Which of the following resistance readings indicates a good fuse?
10 ohms
Infinite ohms
50 ohms
Zero ohms
What would a reading of 120 volts across a fuse indicate?
All of the choices are correct
The fuse is open
120 volts are being lost through the fuse
The fuse should be replaced
A motor with a rating of 15 full load amps is protected by a line voltage overload that keeps opening at a current draw of 14 amps, indicating the overload is ___________.
Shorted
Weak
Too large for the motor
Good
What should the resistance measure across the pilot duty contacts on a pilot duty overload whose line-voltage element is connected to a motor that is turned off?
One ohm
Infinite ohms
Zero ohm
10 ohms
What should the resistance measure through the thermal element of a pilot duty thermal overload?
One ohm
Infinite ohms
10 ohms
Zero ohms
What should the resistance read across the contacts of an open on temperature rise thermostat used on a unit heater if the setpoint of the thermostat is 70°F and the room temperature is 65°F?
One ohm
Zero ohm
Infinite ohms
10 ohms
Why are low-voltage thermostats often more difficult to troubleshoot than line-voltage thermostats?
Low-voltage thermostats are installed in hard access locations
All of the choices are correct
Low-voltage thermostats often have more functions
Low voltage is harder to detect with a voltmeter
Which of the following low-voltage thermostat terminals should be energized when there is a call for heating?
O
W
Y
All of the choices are correct
When should 24 volts be read between the Y and C terminals on a low-voltage heating and cooling thermostat?
When the thermostat is set off
When the thermostat is set to operate continuous fan only
When the thermostat is set to operate in heating
When the thermostat is set to operate in cooling
What should the resistance of the contacts read on a low-pressure switch with a cut-out setting of 20 psig and a cut-in setting of 50 psig if the system pressure is 75 psig?
Infinite ohms
24 ohms
Zero ohms
10 ohms
Which choice best describes the condition of a control transformer if the resistance of the primary winding is 25 ohms, and the secondary winding is one ohm?
Shorted
Good
Open
Bad
Sequencers are commonly used to control electric resistance heaters, and they act much like a _____________________.
Time-delay relay
Contactor
Thermal overload
Circuit breaker
Switching relay
When the furnace is off and cool, the limit switches should have a resistance of ______________.
Infinite ohms
10 ohms
Zero ohm
100 ohms
Which of the following conditions can cause the pilot flame to go out when the knob or lever on the combination gas valve is released?
A pilot flame is not touching the thermocouple
Faulty thermocouple
All the conditions could cause the pilot flame to go out
Faulty pilot solenoid
What is a method of checking the flame rectification circuit to sense the flame in gas furnaces?
Check to see if 24 volts is being supplied to the flame sensor using an AC voltmeter
Check for DC microvolts using a voltmeter
Check for DC amps by placing the amp-on ammeter around the wire to the flame rod
Check for DC microamps by placing a microammeter in series with the flame rod or system ground
What should a technician check if the burner does not start on an oil furnace using a cad cell primary control?
Check to ensure the thermostat is closing to call for heat
All of the checks should be made by the technician
Check the power supply to the primary control
Check all of the limit switches to ensure they are closed
A cad cell primary control can be checked by connecting a resistor between the F terminals with ________________ of resistance.
15,000 ohms
1500 ohms
150 ohms
15 ohms
When troubleshooting a switch to determine if it is malfunctioning, the technician must know the ________________ of the switch in the system.
Location
Function
Off position resistance
Layout
What are the three areas of malfunction possible in a contactor?
Coil, coil holder, and contacts
Contacts, mechanical linkage, and frame
Coil, coil holder, and mechanical linkage
Coil, contacts, and mechanical linkage
Which of the following items could assist the technician in correctly diagnosing problems in HVAC equipment?
Installation and service manuals
All of the choices are correct
Troubleshooting charts
Self-diagnostic features
What is the purpose of a troubleshooting chart?
Help the installation technician to use proper installation techniques
Guide the technician through a systematic approach to troubleshooting HVAC systems
Aid the technician in reading wiring diagrams enabling them to troubleshoot electrical problems in HVAC equipment
A guide to help the homeowner troubleshoot and repair their HVAC unit
What should be one of the first steps a technician takes when troubleshooting a residential air conditioning system?
Check to see if correct line- and low-voltage is available to the system
Check the running capacitor
Check the resistance of the compressor motor
Check the indoor fan motor
What should be the next step taken if a technician has determined that line-voltage and control voltage are available to an HVAC system that will not operate?
Replace the thermostat
Check the capacitance of the run capacitor
Measure the resistance of the compressor motor
Isolate the circuit that contains the fault
Which of the following choices describes a method to check the condition of a control transformer?
Check the resistance of the transformer’s windings
All of the choices are correct
Check to ensure proper low-voltage is being produced by the transformer
Check for proper line-voltage to the transformer
What is the likely cause of a PSC condenser fan motor that will not start in a residential condensing unit if the compressor operates and the fan motor is warm to the touch?
Open contactor coil
Faulty capacitor
Shorted compressor winding
Open transformer winding
Which of the following conditions can cause a motor to draw higher than normal amperage?
Faulty running capacitor
Worn or tight bearings
Higher than normal mechanical load on the motor
All of the choices are correct
What items are commonly given on troubleshooting charts for HVAC equipment?
All of the choices are correct
Necessary remedy or repair action to correct the problem
Causes of the symptoms
Symptoms of improper operation
Which of the following scenarios gives an example of troubleshooting using the hopscotching method?
Checking the resistance of a pressure switch in a control circuit
Checking the condition of the switches in a control circuit by checking the voltage at L1 and L2, then proceeding from one switch to the next in the circuit until the open switch is located
Checking the mechanical condition of the load in the circuit
Checking the resistance of the load in a circuit
Which of the following voltage measurements indicates an open control device in the circuit whose diagram is shown below?
230 volts read across OL
Zero volts read across T
Zero volts read across DLT
Zero volts read across the HP
What procedure is one of the easiest ways to check the condition of the switches in an energized electrical circuit?
Hopscotching
Current check
Millivolt check
Resistance check
A service technician should never leave a conditioned air system with a safety control device ____________________.
Jumped out
Replaced with the incorrect part
Removed from the circuit
All of the choices are correct
Which of the following conditions can result in a blown low-voltage fuse in an air conditioning control system?
All of the choices are correct
Shorted contactor coil
Damaged control wiring
Incorrect control wiring connections
Which of the following components can be checked in a packaged unit if the technician positions the fan switch on the thermostat to the “Fan On” position?
Compressor
Condenser fan motor
Transformer
Crankcase heater
