HVAC Practice Exam

Take this free HVAC practice exam to study for your HVAC test.

HVAC practice exams can be used for professional-growth and to prepare for certification exams. Many states require a license to work as an HVAC tech. Even if a state does not require a license, often employers require certification. To work with refrigerants, the EPA requires a Section 608 certification regardless of state requirements.

For comprenhensive coverage of HVAC subjects that will be tested on all HVAC certiciation tests, use our 300 question HVACR Practice Exams. Our test was developed by HVAC Excellence, the largest provider of certifications in the HVACR industry. A 100 question EPA 608 practice test comes with our materials. Our interactive test platform allows you to simulate the exam. Take as many tests as you like. There's no time limit or recurring charges.

For more information on the HVAC industry and test prep, see our HVAC Study Guide.

For additional free practice, use our HVAC Practice Test.

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Principles of Electrical and Refrigeration Theory

1 What is the symbol for impedance?

a. R

b. I

c. Z

d. P

Incorrect. Please choose another answer.

The symbol or letter for impedance is Z and it is represented by writing its magnitude and phase.

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2 The safety ground conductor for A/C circuit is usually color coded _________.

a. red

b. green

c. black

d. white

Incorrect. Please choose another answer.

The NEC and NFPA has designated green as a ground.

Air Conditioning

3 Heat which causes a change in temperature of a substance is called:

a. latent heat.

b. sensible heat.

c. superheat.

d. regular heat.

Incorrect. Please choose another answer.

Any time there is a change of temperature indicated by the thermometer the heat level or intensity can easily be measured. In the writings of the early scientists who provided the foundations of thermodynamics, sensible heat had a clear meaning in calorimetric.

4 What is heat, which causes a change in the state of a material without a change in temperature, called?

a. Latent heat

b. Sensible heat

c. Superheat

d. Regular heat

Incorrect. Please choose another answer.

Heat, which causes a change of state without a change in temperature, is known as latent heat. An example of latent heat is water changing to ice or vice a versa. Latent heat is the heat released or absorbed by a body or a thermodynamic system during a process that occurs without a change in temperature.

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Commercial Air Conditioning

5 What is a sling psychrometer used to measure?

a. Latent heat

b. Super heat

c. Wet and dry bulb temperature

d. Barometric pressure

Incorrect. Please choose another answer.

A sling psychrometer is a device that consist of two thermometers fitted in a hinged bracket used for spinning the two thermometers. One of the bulbs is kept moist with distilled water on a sock or wick placed over the thermometer's tip. As the thermometers are rotated, evaporation of water from the wick lowers the temperature indicating a lower temperature than that of the dry-bulb thermometer. This is the Wet bulb temperature which will be lower than the dry bulb and can never be above dry bulb measurement. The lower the relative humidity, the lower the wet bulb temperature. The difference in the two bulbs readings can be applied to a psychrometric chart to calculate relative humidity and other properties of air.

6 A compressor is operating with a discharge pressure of 235.3 psig and a suction pressure of 35.3 psig. What is the compression ratio (pumping ratio)?

a. 10:1

b. 8:1

c. 7:1

d. 5:1

Incorrect. Please choose another answer.

Compression ratio is found by dividing the absolute discharge pressure by the absolute suction pressure. PSIG is converted to absolute by adding 14.7 to the pressure.

In this problem, discharge pressure 235.3 plus 14.7 equals 250 PSIA and the suction pressure 35.3 plus 14.7 equals 50 PSIA.

250/50 = 5

The ratio is 5 to 1

Commercial Refrigeration

7 In a (direct expansion) evaporator, liquid refrigerant must boil away as close to the end of the coil as possible in order to:

a. ensure proper oil return.

b. ensure that frost does not accumulate.

c. sub-cool the compressor.

d. operate at high efficiency.

Incorrect. Please choose another answer.

Direct type evaporators are designed to operate most efficiently with approximately 10 degrees superheat. In order to have superheat, all liquid must be boiled away before reaching the end of the evaporator.

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8 A thermal expansion valve that is stuck wide open will cause ___________.

a. low suction pressure

b. a flooded evaporator

c. excessive superheat

d. a starved evaporator

Incorrect. Please choose another answer.

A valve that is in the maximum open position will have liquid refrigerant flowing at a rate faster than the evaporator could boil it away; thus creating a flooded coil and liquid refrigerant going back to the compressor.

Heat Pump Service

9 What is the major difference between a heat pump and an air conditioner?

a. Condenser

b. Thermostatic expansion valve

c. Evaporator

d. Reversing valve

Incorrect. Please choose another answer.

The reversing valve is the component that will reverse the flow of refrigerant when changing from air conditioning to heating.

10 What device controls the supplementary electric heat according to the outdoor temperature?

a. Auxiliary temperature control

b. Outdoor auxiliary thermostat

c. Outdoor ambient thermostat

d. Indoor thermostat only

Incorrect. Please choose another answer.

To control energy, the heat pump will incorporate outdoor thermostats to limit the auxiliary heat before the balance point is reached.

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Heat Pump Installation

11 Which of the following is not a factor that should be considered when installing an outdoor unit?

a. Return air

b. Wind factors

c. Sound transmission

d. Snow fall

Incorrect. Please choose another answer.

When installing the outdoor unit the return air is not a factor in the installation; all of the other answers are factors involving installation.

12 What is the minimum clearance for access panels on an outdoor condensing unit?

a. 36 inches

b. 30 inches

c. 15 inches

d. 10 inches

Incorrect. Please choose another answer.

Most manufacturers recommend 30 inches of clearance from the structure, bushes, hedges and any other obstructions.

Gas, Oil and Combustion

13 One BTU is the amount of heat required to raise the temperature of:

a. one pound of ice one-degree Fahrenheit.

b. one pound of water one-degree Fahrenheit.

c. one gallon of water one-degree Fahrenheit.

d. one gallon of water eight degrees Fahrenheit.

Incorrect. Please choose another answer.

One BTU is the quantity of heat required to raise the temperature of one pound of water one degree Fahrenheit. The pound of water absorbs 1 BTU of energy to change from 68°F to 69°F.

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14 What is the primary composition of natural gas?

a. 65 percent methane

b. 75 percent methane

c. 85 percent methane

d. 95 percent methane

Incorrect. Please choose another answer.

Natural gas distributed for consumer use is 95.4 % Methane, 2.2 % Ethane, 1.6 % Nitrogen, 0.5 % Carbon Dioxide, 0.2 % Propane, .04% butane, .01% Oxygen and .05 % miscellaneous gases.

Electric Heat

15 The electric heat element is usually made of what material?

a. Copper with a brass coating

b. Nickel with a cadmium coating

c. Nickel and steel

d. Nickel and chromium

Incorrect. Please choose another answer.

Heat elements are made of Ni-chrome which is nickel and chromium. They are combined to create a resistance wire.

16 Which of the following is an example of a resistive load?

a. Bimetal switch

b. Crankcase heater

c. Transformer

d. Motor

Incorrect. Please choose another answer.

A resistive load is an electrical load in which voltage and current are in phase and are converted to energy in the form of heat. Other examples of a resistive load are electrical heaters and incandescent bulbs.

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Residential Heat Load Calculation

17 An oversized heating and cooling system can cause which of the following?

a. Operating cost and relative humidity in the structure will decrease significantly.

b. Moisture damage to a furnace heat exchanger and inadequate humidity removal during cooling cycles.

c. The structure will develop low humidity levels in the cooling season and high humidity in the winter.

d. Equipment will last longer and require less energy to operate due to the shorter run time.

Incorrect. Please choose another answer.

Over sizing a system will cause short cycling which will cause moisture problems. In the summer, not enough moisture will be removed making the structure uncomfortable with very poor energy usage. In the winter, the system will not heat up enough causing moisture to condense in the heat exchanger, as well as the venting system, shortening the life of the system.

18 When the temperatures of a structure both inside and outside are equal, there is _____.

a. no heat transfer

b. latent heat transfer to the outside

c. thermal heat transfer of sensible heat

d. a lower rate of relative humidity

Incorrect. Please choose another answer.

In order for heat to transfer there must be a difference in temperature. This follows the second law of thermodynamics. (Heat travels from a warmer area to cooler area.)

Low-GWP Refrigerant Safety and Training

19 Polyolester (POE) oils stored in plastic containers will _______.

a. separate

b. become more alkaline

c. become acidic

d. absorb moisture through the plastic

Incorrect. Please choose another answer.

Polyolester (POE) Oils are very hygroscopic and must be stored in a metal containers. Plastic containers may be permeable to moisture.

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20 R-407C has _______.

a. a foul odor

b. to be charged in the vapor phase

c. the ability to fractionate

d. no temperature glide

Incorrect. Please choose another answer.

R-407C is a near-azeotropic ternary blend of hydrofluorocarbons refrigerants. It contains difluoromethane (R-32), pentafluoroethane (R-125) and 1,1,1,2-tetrafluoroethane (R-134a) which all have different pressure temperature relationships.

Green Awareness

21 What is a carbon footprint?

a. The carbon deposits from burning gasoline.

b. The amount of carbon dioxide that is produced to support your lifestyle.

c. The amount of carbon in the atmosphere produced by the world's lifestyle.

d. The amount of carbon in the stratosphere.

Incorrect. Please choose another answer.

A carbon footprint is an estimate of how much carbon dioxide is produced to support a person's lifestyle. Essentially, it measures an individual's impact on the climate based on how much carbon dioxide the person produces. Factors that contribute to a carbon footprint include the individual's travel methods and general home energy usage.

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22 What is energy management?

a. A rule that the total amount of energy stays constant in an isolated system over time.

b. Recovering energy lost while using mechanical equipment.

c. Reading the electric and fuel gas meters every month.

d. The monitoring and controlling of energy consuming devices.

Incorrect. Please choose another answer.

Energy management is a very broad term used to cover the entire field of energy and its use. Energy management can be subdivided into more specific areas such as purchase utility, energy consumption and energy demand.