Nate Core exam QUESTIONS AND
ANSWERS 100% CORRECT
What makes a contract legal? - CORRECT ANSWERS Any verbal or written agreement.
Why should hacksaws and power saws not be used when cutting tubing or refrigerant lines? - CORRECT
ANSWERS The small shavings created by the teeth of the saw can enter the tubing and do
damage to the components of the system.
Why should tube cutters be used? - CORRECT ANSWERS They produce a square, clean cut
and leave no shavings to contaminate the system.
What can be used to cut capillary tubing? - CORRECT ANSWERS A triangular file or a knife
edge file.
How should tubing be cut? - CORRECT ANSWERS It should be scored all the way around the
outside and then snapped to prevent closing of the inside diameter.
What can be used to remove a burr on the inside of tubing? - CORRECT ANSWERS Reamers
and deburrers.
What does burring cause on the inside of tubing? - CORRECT ANSWERS It can create
turbulence and pressure drop inside the piping.
What can be used on soft drawn copper to provide a bend without kinking or damaging the tubing? -
CORRECT ANSWERS Tube benders.
Spring-Type benders can only be used on what type of tubbing? - CORRECT ANSWERS Soft
drawn copper
,What is the purpose of a flaring tool? - CORRECT ANSWERS It allows you to join soft drawn
copper tubing without the use of a coupling.
What is the purpose of a swaging tool? - CORRECT ANSWERS A method of joining tubing
without a fitting.
After flaring, swaging, and connecting the tubing, what do you do next? - CORRECT ANSWERS
You either solder or braze the connection.
Describe the glass stem thermometer. - CORRECT ANSWERS It has a liquid filled tube
marked off with a graduated temperature scale.
What are some characteristics of a dial stem thermometer? - CORRECT ANSWERS Not quite
as accurate as the glass stem thermometer, but it is low cost and durable.
What do the glass stem thermometer and the dial stem thermometer measure? - CORRECT ANSWERS
Dry-bulb temperature.
What temperature is in relation to human comfort? - CORRECT ANSWERS Dry-bulb
temperature.
What is a sling psychometer? - CORRECT ANSWERS It combines glass stem thermometers to
measure both dry-bulb and wet-bulb temperatures.
What is needed with the sling psychometer to measure temperatures? - CORRECT ANSWERS
A psychometric chart or slide rule.
, What can the dry-bulb and wet-bulb temperatures be used to determine? - CORRECT ANSWERS
Relative humidity (%RH) The dew points. Other properties of the air.
What can be used to calculate the relative humidity, dew point, and other properties of the air? -
CORRECT ANSWERS The difference between the wet-bulb and the dry-bulb temperature.
Explain the effects of relative humidity. - CORRECT ANSWERS By increasing the humidity
during the heating season, the evaporation of moisture is slowed, therefore you feel warmer and vice
versa.
What is the digital psychrometer able to do? - CORRECT ANSWERS It is capable of reading
dry-bulb and wet-bulb temperature and %RH.
How do you find absolute pressure? - CORRECT ANSWERS Gauge pressure + 14.7PSI
What does a pressure gauge use as the operating element? - CORRECT ANSWERS A bourdon
tube.
Describe the manifold gauge set. - CORRECT ANSWERS On the right = High pressure (Liquid)
(discharge gauge) (Red) On the left = Compound or suction gauge (Blue) (Vapor)
What is often used to measure pressure drop? (The difference in pressure between two points.) -
CORRECT ANSWERS Differential pressure gauges.
What can differential pressure gauges do? - CORRECT ANSWERS They can calculate air flow.
They can help you determine how clean or dirty a coil or filter is. Provides simultaneous pressure and
flow measurements
Before you charge a system with refrigerant or after you have replaced a component or repaired a leak,
you should? - CORRECT ANSWERS Remove all air and moisture from the system.
ANSWERS 100% CORRECT
What makes a contract legal? - CORRECT ANSWERS Any verbal or written agreement.
Why should hacksaws and power saws not be used when cutting tubing or refrigerant lines? - CORRECT
ANSWERS The small shavings created by the teeth of the saw can enter the tubing and do
damage to the components of the system.
Why should tube cutters be used? - CORRECT ANSWERS They produce a square, clean cut
and leave no shavings to contaminate the system.
What can be used to cut capillary tubing? - CORRECT ANSWERS A triangular file or a knife
edge file.
How should tubing be cut? - CORRECT ANSWERS It should be scored all the way around the
outside and then snapped to prevent closing of the inside diameter.
What can be used to remove a burr on the inside of tubing? - CORRECT ANSWERS Reamers
and deburrers.
What does burring cause on the inside of tubing? - CORRECT ANSWERS It can create
turbulence and pressure drop inside the piping.
What can be used on soft drawn copper to provide a bend without kinking or damaging the tubing? -
CORRECT ANSWERS Tube benders.
Spring-Type benders can only be used on what type of tubbing? - CORRECT ANSWERS Soft
drawn copper
,What is the purpose of a flaring tool? - CORRECT ANSWERS It allows you to join soft drawn
copper tubing without the use of a coupling.
What is the purpose of a swaging tool? - CORRECT ANSWERS A method of joining tubing
without a fitting.
After flaring, swaging, and connecting the tubing, what do you do next? - CORRECT ANSWERS
You either solder or braze the connection.
Describe the glass stem thermometer. - CORRECT ANSWERS It has a liquid filled tube
marked off with a graduated temperature scale.
What are some characteristics of a dial stem thermometer? - CORRECT ANSWERS Not quite
as accurate as the glass stem thermometer, but it is low cost and durable.
What do the glass stem thermometer and the dial stem thermometer measure? - CORRECT ANSWERS
Dry-bulb temperature.
What temperature is in relation to human comfort? - CORRECT ANSWERS Dry-bulb
temperature.
What is a sling psychometer? - CORRECT ANSWERS It combines glass stem thermometers to
measure both dry-bulb and wet-bulb temperatures.
What is needed with the sling psychometer to measure temperatures? - CORRECT ANSWERS
A psychometric chart or slide rule.
, What can the dry-bulb and wet-bulb temperatures be used to determine? - CORRECT ANSWERS
Relative humidity (%RH) The dew points. Other properties of the air.
What can be used to calculate the relative humidity, dew point, and other properties of the air? -
CORRECT ANSWERS The difference between the wet-bulb and the dry-bulb temperature.
Explain the effects of relative humidity. - CORRECT ANSWERS By increasing the humidity
during the heating season, the evaporation of moisture is slowed, therefore you feel warmer and vice
versa.
What is the digital psychrometer able to do? - CORRECT ANSWERS It is capable of reading
dry-bulb and wet-bulb temperature and %RH.
How do you find absolute pressure? - CORRECT ANSWERS Gauge pressure + 14.7PSI
What does a pressure gauge use as the operating element? - CORRECT ANSWERS A bourdon
tube.
Describe the manifold gauge set. - CORRECT ANSWERS On the right = High pressure (Liquid)
(discharge gauge) (Red) On the left = Compound or suction gauge (Blue) (Vapor)
What is often used to measure pressure drop? (The difference in pressure between two points.) -
CORRECT ANSWERS Differential pressure gauges.
What can differential pressure gauges do? - CORRECT ANSWERS They can calculate air flow.
They can help you determine how clean or dirty a coil or filter is. Provides simultaneous pressure and
flow measurements
Before you charge a system with refrigerant or after you have replaced a component or repaired a leak,
you should? - CORRECT ANSWERS Remove all air and moisture from the system.
