NATE AC Service Certification Exam
Questions and Correct Answers
Question 1
With the thermostat blower switch set to ON, which of the following measurements
indicates a call for residential indoor blower operation?
A. 0 volts at the load side of the relay
B. 24 volts at the load side of the relay
C. 0 volts at the relay coil
D. 24 volts at the relay coil
Correct Answer
*B
Question 2
Outdoor condensing units that are installed in areas where flooding is possible must:
A. be mounted above flood level.
B. utilize NEMA 1 enclosures.
C. be mounted under an overhanging eave.
D. use water resistant components.
Correct Answer
A. be mounted above flood level.
Question 3
Will a Capacitor Start-Capacitor Run (CSCR) motor that has an open run capacitor
start?
A. No, it would be unable to start without the run capacitor
B. It may start, but it draws a higher than normal running current
C. Yes, it will start, but it will run backwards
D. It can only start if the voltage is higher
Correct Answer
*A
Page 1 of 34
,Question 4
A delay on make relay delays load:
A. from de-energizing for a fixed time period after cycle.
B. from energizing for a fixed time period after cycle.
C. from energizing for a fixed time period at the start of cycle.
D. from de-energizing for a fixed time period at start of cycle.
Correct Answer
*B
Question 5
What is the purpose of the grounding conductor?
A. Personal and equipment protection
B. Protect against motor overload
C. Provide a neutral conductor
D. To complete the circuit
Correct Answer
A. Personal and equipment protection
Question 6
Service site conditions are:
*House feels "drafty" in cooling,
*Properly sized 3-1/2 ton split system,
*High supply face velocities
*Ductwork is properly sized,
*Total CFM 1400
What do these readings indicate?
A. The system is operating normally and there is nothing wrong
B. The returns are undersized
C. The system is operating normally but the supply registers are too restrictive
D. The blower is set at too high CFM
Correct Answer
C. The system is operating normally but the supply registers are too restrictive
Page 2 of 34
,Question 7
On a residential no cooling call, typically the first check would be:
A. the air filter.
B. the control voltage at the transformer.
C. if the thermostat is calling for cooling.
D. the refrigerant system pressures.
Correct Answer
C. if the thermostat is calling for cooling.
Question 8
What is the typical method of staging a two stage compressor in an air conditioning
system?
A. It is based on the difference between indoor dry bulb temperature
B. It is based on the deviation from the thermostat setpoint
C. The first stage runs the first 70% of run time; the second stage runs the last 30%
D. The second stage runs the first five minutes; the first stage runs the remainder of
the run time
Correct Answer
*B
Question 9
In a economizer system, the enthalpy control is used to measure:
A. moisture content.
B. humidity of ambient air.
C. outside air temperature.
D. both temperature and moisture content.
Correct Answer
*C
Page 3 of 34
, Question 10
What factors should a technician determine when replacing a contactor?
A. Coil voltage, number of poles, and contact ratings
B. Coil voltage, coil henries, number of poles, and contact rating
C. Coil voltage, coil amp draw, wire sizes, and number of poles
D. Coil voltage, coil resistance, number of poles, and coil henries
Correct Answer
*D
Question 11
If an air conditioning system needs to operate in a low ambient condition, the
condenser may become too efficient. What happens to condenser operation and
what can be done to counteract this condition?
A. The head pressure becomes too low and the superheat needs to be lowered
B. The head pressure becomes too low and the superheat needs to be raised
C. The head pressure becomes too low and the condenser fan motor needs to be
slowed or stopped
D. The suction pressure becomes too high and a low ambient controller will lower it
Correct Answer
*B
Question 12
diagram #50 missing page #49
Using the diagram above, what is the voltage across T1 & L1 with the compressor
contactor de-energized and compressor winding intact?
A. 0V
B. Less than 120V
C. 120V
D. 230V
Correct Answer
*
Page 4 of 34
Questions and Correct Answers
Question 1
With the thermostat blower switch set to ON, which of the following measurements
indicates a call for residential indoor blower operation?
A. 0 volts at the load side of the relay
B. 24 volts at the load side of the relay
C. 0 volts at the relay coil
D. 24 volts at the relay coil
Correct Answer
*B
Question 2
Outdoor condensing units that are installed in areas where flooding is possible must:
A. be mounted above flood level.
B. utilize NEMA 1 enclosures.
C. be mounted under an overhanging eave.
D. use water resistant components.
Correct Answer
A. be mounted above flood level.
Question 3
Will a Capacitor Start-Capacitor Run (CSCR) motor that has an open run capacitor
start?
A. No, it would be unable to start without the run capacitor
B. It may start, but it draws a higher than normal running current
C. Yes, it will start, but it will run backwards
D. It can only start if the voltage is higher
Correct Answer
*A
Page 1 of 34
,Question 4
A delay on make relay delays load:
A. from de-energizing for a fixed time period after cycle.
B. from energizing for a fixed time period after cycle.
C. from energizing for a fixed time period at the start of cycle.
D. from de-energizing for a fixed time period at start of cycle.
Correct Answer
*B
Question 5
What is the purpose of the grounding conductor?
A. Personal and equipment protection
B. Protect against motor overload
C. Provide a neutral conductor
D. To complete the circuit
Correct Answer
A. Personal and equipment protection
Question 6
Service site conditions are:
*House feels "drafty" in cooling,
*Properly sized 3-1/2 ton split system,
*High supply face velocities
*Ductwork is properly sized,
*Total CFM 1400
What do these readings indicate?
A. The system is operating normally and there is nothing wrong
B. The returns are undersized
C. The system is operating normally but the supply registers are too restrictive
D. The blower is set at too high CFM
Correct Answer
C. The system is operating normally but the supply registers are too restrictive
Page 2 of 34
,Question 7
On a residential no cooling call, typically the first check would be:
A. the air filter.
B. the control voltage at the transformer.
C. if the thermostat is calling for cooling.
D. the refrigerant system pressures.
Correct Answer
C. if the thermostat is calling for cooling.
Question 8
What is the typical method of staging a two stage compressor in an air conditioning
system?
A. It is based on the difference between indoor dry bulb temperature
B. It is based on the deviation from the thermostat setpoint
C. The first stage runs the first 70% of run time; the second stage runs the last 30%
D. The second stage runs the first five minutes; the first stage runs the remainder of
the run time
Correct Answer
*B
Question 9
In a economizer system, the enthalpy control is used to measure:
A. moisture content.
B. humidity of ambient air.
C. outside air temperature.
D. both temperature and moisture content.
Correct Answer
*C
Page 3 of 34
, Question 10
What factors should a technician determine when replacing a contactor?
A. Coil voltage, number of poles, and contact ratings
B. Coil voltage, coil henries, number of poles, and contact rating
C. Coil voltage, coil amp draw, wire sizes, and number of poles
D. Coil voltage, coil resistance, number of poles, and coil henries
Correct Answer
*D
Question 11
If an air conditioning system needs to operate in a low ambient condition, the
condenser may become too efficient. What happens to condenser operation and
what can be done to counteract this condition?
A. The head pressure becomes too low and the superheat needs to be lowered
B. The head pressure becomes too low and the superheat needs to be raised
C. The head pressure becomes too low and the condenser fan motor needs to be
slowed or stopped
D. The suction pressure becomes too high and a low ambient controller will lower it
Correct Answer
*B
Question 12
diagram #50 missing page #49
Using the diagram above, what is the voltage across T1 & L1 with the compressor
contactor de-energized and compressor winding intact?
A. 0V
B. Less than 120V
C. 120V
D. 230V
Correct Answer
*
Page 4 of 34
