North Carolina HVAC Practice Test (Free)

Question 1

A technician measures high superheat and low subcooling on a fixed-orifice metering device system. What does this most likely indicate?

Accepted Answer

Undercharge of refrigerant

Answer

A dirty condenser coil

Answer

A failed compressor valve

Answer

Overcharge of refrigerant

Question 2

Under EPA regulations, what must a technician do before opening a system containing more than a minimal amount of refrigerant for service?

Accepted Answer

Recover the refrigerant using certified recovery equipment

Answer

Vent the refrigerant to the atmosphere to save time

Answer

Add more refrigerant before servicing

Answer

Disconnect the thermostat only

Question 3

In a gas furnace, what is the function of the heat exchanger?

Accepted Answer

It transfers heat from combustion gases to circulating air without mixing the two airstreams

Answer

It filters dust from the return air

Answer

It mixes fuel and air before ignition

Answer

It vents combustion byproducts directly into the living space

Question 4

What does subcooling measure in a refrigeration system?

Accepted Answer

How many degrees the liquid refrigerant is below its saturation temperature at the condenser

Answer

The indoor thermostat setpoint

Answer

How many degrees the vapor is above its saturation temperature at the evaporator

Answer

The ambient outdoor temperature

Question 5

What is the general purpose of a filter drier installed in a refrigeration line?

Accepted Answer

To remove moisture and particulate contaminants from the refrigerant

Answer

To measure superheat directly

Answer

To increase compressor speed

Answer

To boost refrigerant pressure

Question 6

Which refrigeration component increases the pressure and temperature of the refrigerant vapor?

Accepted Answer

Compressor

Answer

Expansion valve

Answer

Filter drier

Answer

Evaporator

Question 7

What is the main advantage of a two-stage or modulating gas furnace over a single-stage furnace?

Accepted Answer

It can run at a lower output most of the time, improving comfort and efficiency

Answer

It eliminates the need for a heat exchanger

Answer

It uses only electric resistance heat

Answer

It never needs a filter

Question 8

In North Carolina, what is the purpose of a limit switch on a gas furnace?

Accepted Answer

To shut off the burners if the plenum air temperature gets too high

Answer

To control the thermostat display

Answer

To ignite the pilot light

Answer

To measure outdoor humidity

Question 9

Under EPA Section 608, which certification type is required to service small appliances containing refrigerant, such as household refrigerators?

Accepted Answer

Type I

Answer

Type II

Answer

Type III

Answer

Universal only

Question 10

A heat pump in heating mode loses capacity as outdoor temperature drops. What is the common solution used to maintain comfort during very cold weather?

Accepted Answer

Activating supplemental electric resistance heat strips

Answer

Increasing refrigerant charge above the nameplate rating

Answer

Disabling the defrost cycle

Answer

Reversing the refrigerant flow permanently

North Carolina HVAC Practice Test

Question 1

A technician measures high superheat and low subcooling on a fixed-orifice metering device system. What does this most likely indicate?

Question 2

Under EPA regulations, what must a technician do before opening a system containing more than a minimal amount of refrigerant for service?

Question 3

In a gas furnace, what is the function of the heat exchanger?

Question 4

What does subcooling measure in a refrigeration system?

Question 5

What is the general purpose of a filter drier installed in a refrigeration line?

Question 6

Which refrigeration component increases the pressure and temperature of the refrigerant vapor?

Question 7

What is the main advantage of a two-stage or modulating gas furnace over a single-stage furnace?

Question 8

In North Carolina, what is the purpose of a limit switch on a gas furnace?

Question 9

Under EPA Section 608, which certification type is required to service small appliances containing refrigerant, such as household refrigerators?

Question 10

A heat pump in heating mode loses capacity as outdoor temperature drops. What is the common solution used to maintain comfort during very cold weather?

Question 11

In the basic refrigeration cycle, where does the refrigerant absorb heat from the space being cooled?

Question 12

Under federal refrigerant handling rules, what is the general term for capturing refrigerant from a system and storing it in an external container without necessarily testing or processing it?