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NATE_CORE NEC 2023

NATE Core Practice Test 2

This practice test covers the tools and test instruments every HVACR technician relies on daily. You will see questions on hand tools like tubing cutters, flaring tools, and torque wrenches, plus test instruments like the multimeter, manifold gauge set, clamp-on ammeter, micron gauge, megohmmeter, and combustion analyzer.

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NATE Core

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Frequently Asked Questions

Yes — completely free with no signup required. Every question includes a full explanation of the correct answer.

Two: the NATE Core exam plus at least one specialty exam (for example AC Service, Heat Pump Service, or Air Distribution Service). You can take them on the same day or separately.

The Core exam has 50 questions and each installation or service specialty exam has 100 questions. You need 70% on each to pass — 35 of 50 on Core and 70 of 100 on a specialty. Check natex.org for the current format before you book.

NATE certification lasts two years. To renew, you submit 16 hours of continuing education or retake the specialty exam before your certification expires.

No. These are independent practice tests written to match the published NATE exam topics. They are not official NATE exam questions.

Exam Tip: Match the tool to the job. Cutting tubing, flaring a joint, and reading voltage each need a different, specific tool — knowing which is which is a common exam focus.

30

Questions

30 min

Time

70%

Pass

Timer starts immediately. Progress is auto-saved.

NATE Core Practice Test 2 — Question List

Question 1: What is a nut driver primarily used for?

Cutting copper tubing
Turning hex-head screws and fasteners
Measuring refrigerant pressure
Flaring the end of a tube

Question 2: What tool is used to cut copper refrigerant tubing to length?

Flaring tool
Swaging tool
Tubing cutter
Torque wrench

Question 3: What does a flaring tool do to the end of a copper tube?

Bends it to a 90-degree angle
Removes the outer coating
Expands its diameter to fit inside another pipe
Shapes it into a cone so it can be sealed with a flare fitting

Question 4: What is the purpose of a swaging tool?

To expand the end of one tube so another tube of the same size can slide inside it
To measure the voltage in a circuit
To bend sheet metal duct corners
To tighten bolts to a specific torque

Question 5: Why would a technician use a torque wrench when installing certain fasteners?

To make the fastener spin faster
To tighten the fastener to a specific, manufacturer-recommended amount of force
To measure the length of the fastener
To test if the fastener conducts electricity

Question 6: Which of these can a standard multimeter measure?

Refrigerant pressure
Air velocity
Voltage, current, and resistance
Relative humidity

Question 7: What is a manifold gauge set used for?

Measuring air temperature
Testing electrical continuity
Measuring humidity levels
Reading refrigerant pressures in a system

Question 8: What does a clamp-on ammeter measure?

Electrical current flowing through a wire
The temperature of a motor
The pressure inside a refrigerant line
The humidity in a duct

Question 9: Which instrument would a technician use to check the supply air temperature coming out of a vent?

Manifold gauge set
Thermometer
Torque wrench
Nut driver

Question 10: A technician uses a multimeter set to the resistance (ohms) setting to test a component. What is this typically used to check?

The voltage available at the component while it runs
If the compressor is the right physical size
If a component, like a motor winding, is open, shorted, or within its normal resistance range
If the refrigerant charge is correct

Question 11: A technician has finished evacuating a system. Which instrument confirms that a deep vacuum, such as 500 microns, has actually been reached?

The low-side compound gauge on the manifold
A clamp-on ammeter on the vacuum pump
A manometer reading in inches of water column
A micron (vacuum) gauge

Question 12: A technician connects a manifold gauge set to a system to check performance. What two pressures will the gauges typically show?

High-side pressure and low-side pressure
Indoor and outdoor temperature
Voltage and amperage
Dry bulb and wet bulb temperature

Question 13: What can happen if a fitting is tightened without a torque wrench and ends up over-tightened?

The fitting will run more efficiently
The fitting or threads can be damaged, which may cause a leak
The refrigerant charge will automatically adjust
The voltage in the circuit will increase

Question 14: A technician suspects a wall thermostat wire is broken. Which multimeter setting would help check for a break in the wire?

Amperage (current)
Frequency
Continuity or resistance
Capacitance only

Question 15: A technician wants to check the running amp draw of a compressor without disconnecting any wires. What tool should be used?

Torque wrench
Tubing cutter
Manifold gauge set
Clamp-on ammeter

Question 16: Besides simple air temperature, what else might a technician use a thermometer with a probe for?

Checking the temperature of a refrigerant line or a water pipe directly
Measuring electrical resistance
Measuring refrigerant pressure
Cutting copper tubing

Question 17: Which instrument is used to test the insulation resistance between a compressor's motor windings and ground?

Clamp-on ammeter
Megohmmeter
Micron gauge
Capacitance meter

Question 18: What is the main difference between flaring and swaging a copper tube?

Flaring cuts the tube; swaging bends the tube
Flaring and swaging are two names for the same process
Flaring shapes a cone on the tube end for a fitting; swaging expands the tube end to accept another tube
Flaring is used only on steel pipe; swaging is used only on copper

Question 19: A technician notices the low-side pressure on the manifold gauges is much lower than expected. What might this suggest?

The thermostat batteries are low
The circuit breaker tripped
The air filter was just replaced
There may be a refrigerant charge or airflow problem in the system

Question 20: Why should a technician regularly check that hand tools like nut drivers and wrenches are in good condition?

Worn or damaged tools can slip and cause injury or damage to equipment
New tools are more expensive to replace
Worn tools give less accurate torque readings, but are otherwise safe
OSHA requires all hand tools to be replaced every year

Question 21: Why do technicians flow a small amount of dry nitrogen through copper tubing while brazing?

To cool the joint so the filler metal sets faster
To keep oxygen out of the tube so copper oxide scale does not form inside
To pressure-test the joint while the alloy is still molten
To raise the melting temperature of the filler rod

Question 22: On a standard manifold gauge set, what does the blue hose typically connect to?

The high-side (discharge) port
A vacuum pump only
The low-side (suction) port
The electrical test leads

Question 23: A manufacturer specifies a certain torque value, in foot-pounds, for a fitting. Why is it important to follow this exact value?

Tighter is always better, so the value is only a minimum
It is only a suggestion and has no real effect
It determines the refrigerant type used
It ensures the fitting is tight enough to seal without being overtightened and damaged

Question 24: How is a clamp-on ammeter different from using a standard multimeter's amperage setting?

A clamp-on ammeter measures current without needing to break the circuit open
A clamp-on ammeter can only measure voltage
A clamp-on ammeter measures refrigerant pressure instead of current
There is no difference; they are the same tool

Question 25: After cutting a copper tube with a tubing cutter, small metal burrs are often left on the inside edge. What should the technician do?

Leave the burrs in place; they do not matter
Remove the burrs with a reaming tool before making the connection
Heat the tube until the burrs melt away
Cut the tube again in the same spot

Question 26: On a manifold gauge set, what is the yellow hose typically used for?

Reading only the high-side pressure
Testing electrical voltage
Connecting to a vacuum pump, refrigerant tank, or recovery machine
Measuring air temperature

Question 27: A technician measures both the supply air temperature and the return air temperature of a system. Why is this comparison useful?

It tells the technician the exact refrigerant charge
It shows the electrical resistance of the blower motor
It measures the humidity of the outside air
It helps show how much the system is cooling or heating the air as it passes through

Question 28: Which instrument measures oxygen, carbon monoxide, and flue gas temperature to evaluate how a fuel-burning appliance is operating?

Manometer
Sling psychrometer
Combustion analyzer
Electronic refrigerant leak detector

Question 29: Many multimeters have a continuity setting that beeps. What does this setting help a technician quickly check?

The outdoor temperature
Whether a wire or fuse has a complete, unbroken path for current
The exact refrigerant pressure
The humidity level in a room

Question 30: A technician is installing a new flare fitting and has both a torque wrench and the manufacturer's torque specification sheet. What is the best practice?

Ignore the spec sheet and tighten by feel
Tighten the fitting as much as physically possible
Use the torque wrench to tighten the fitting to the exact spec listed
Skip the torque wrench since flare fittings do not need it

EXAM CARD NATE_CORE

Questions30

Time limit30 min

Pass score70%

Code editionNEC 2023

DifficultyIntermediate

Last reviewedJun 2026

Timer starts immediately. Progress is auto-saved.

Source: NEC 2026 (NFPA 70)