A 24-volt thermostat circuit switches a line-voltage blower motor through a relay. What is a relay?Wikipedia, Relay. Written to NOCTI HVAC (3045), Electricity
A 35-microfarad and a 5-microfarad capacitor are wired in parallel. What is the total capacitance?Wikipedia, Series and parallel circuits, Capacitors. Written to NOCTI HVAC (3045), Electricity; the arithmetic was worked twice
A 240-volt heating element has a resistance of 12 ohms. How much current does it draw?US Army correspondence subcourse OD1747, Refrigeration and Air Conditioning I, lesson 1. Written to NOCTI HVAC (3045), Electricity; the arithmetic was worked twice
A control transformer takes in 120 volts and puts out 24 volts. What type is it?Wikipedia, Transformer. Written to NOCTI HVAC (3045), Electricity
Three loads are wired in series across a supply. What is the same for all three?US Army correspondence subcourse OD1747, Refrigeration and Air Conditioning I, lesson 1. Written to NOCTI HVAC (3045), Electricity
What does a run capacitor do for a single-phase compressor motor?Wikipedia, Motor capacitor. Written to NOCTI HVAC (3045), Electricity
Which meter reads the current in a compressor lead without the circuit being opened?Wikipedia, Current clamp. Written to NOCTI HVAC (3045), Electricity
Show all 60 questions (53 more)
Soldering, Brazing, and Welding 4
Copper tubing is brazed with dry nitrogen flowing through it. What does the nitrogen prevent?Wikipedia, Brazing, Flux. Written to NOCTI HVAC (3045), Soldering, Brazing, and Welding
In a brazed joint, what draws the molten filler metal into the gap between the tube and the fitting?Wikipedia, Brazing. Written to NOCTI HVAC (3045), Soldering, Brazing, and Welding
Which copper tube is made for air conditioning and refrigeration work, as opposed to plumbing tube?Wikipedia, Copper tubing. Written to NOCTI HVAC (3045), Soldering, Brazing, and Welding
Which filler-metal melting temperature is the usual dividing line between soldering and brazing?Wikipedia, Soldering, Soldering vs. brazing. Written to NOCTI HVAC (3045), Soldering, Brazing, and Welding
Pipefitting 2
On a hot-water heating plan, the water leaves each radiator through separate return piping. Which system is drawn?US Army FM 3-34.471, Plumbing, Pipe Fitting, and Sewerage (2001), chapter 2. Written to NOCTI HVAC (3045), Pipefitting
Which valve is made for regulating the flow in a line, with a disc that closes on a ring seat?Wikipedia, Globe valve. Written to NOCTI HVAC (3045), Pipefitting
Controls 3
What does a thermostatic expansion valve (TXV) regulate?Wikipedia, Thermal expansion valve. Written to NOCTI HVAC (3045), Controls
What does the anticipator in a heating thermostat do?Wikipedia, Thermostat, Construction and control. Written to NOCTI HVAC (3045), Controls
Which metering device is a fixed restriction that does not react to temperature?Wikipedia, Thermal expansion valve. Written to NOCTI HVAC (3045), Controls
Installation and Service 2
In a refrigeration system, what is the receiver?US Army correspondence subcourse OD1747, Refrigeration and Air Conditioning I, lesson 1. Written to NOCTI HVAC (3045), Installation and Service
What is a halide torch used for on a refrigeration system?US Army correspondence subcourse OD1747, Refrigeration and Air Conditioning I, lesson 1. Written to NOCTI HVAC (3045), Installation and Service
Related Math and Science 3
A condensing unit is rated at 3 tons of refrigeration. What is that in Btu per hour?Wikipedia, Ton of refrigeration. Written to NOCTI HVAC (3045), Related Math and Science; the arithmetic was worked twice
A supply air thermometer reads 77 degrees Fahrenheit. What is that in degrees Celsius?Written to the NOCTI Job Ready Credential Blueprint for Heating, Ventilation, and Air Conditioning (3045), Related Math and Science; the answer is arithmetic on the numbers in the question, worked twice
How many Btu does it take to raise 10 pounds of water from 60 to 80 degrees Fahrenheit?US Army correspondence subcourse OD1747, Refrigeration and Air Conditioning I, lesson 1. Written to NOCTI HVAC (3045), Related Math and Science; the arithmetic was worked twice
Refrigeration 4
How does a centrifugal compressor raise the pressure of the refrigerant?Wikipedia, Centrifugal compressor. Written to NOCTI HVAC (3045), Refrigeration
Ice at 32 degrees F melts into water at 32 degrees F. What is the heat it takes in called?US Army correspondence subcourse OD1747, Refrigeration and Air Conditioning I, lesson 1. Written to NOCTI HVAC (3045), Refrigeration
Suction vapor leaves an evaporator 10 degrees warmer than its boiling temperature at that pressure. What is the 10 degrees called?US Army correspondence subcourse OD1747, Refrigeration and Air Conditioning I, glossary. Written to NOCTI HVAC (3045), Refrigeration
What drives the cooling process in an absorption refrigeration system?Wikipedia, Absorption refrigerator. Written to NOCTI HVAC (3045), Refrigeration
Refrigerant Recovery 2
R-410A is a blend. Which two refrigerants is it mixed from?Wikipedia, R-410A. Written to NOCTI HVAC (3045), Refrigerant Recovery
Recovered refrigerant is reprocessed to the purity specification and checked to verify it meets it. Which term in the federal rule names this?40 CFR 82.152 (ecfr.gov). Written to NOCTI HVAC (3045), Refrigerant Recovery
General Safety 4
A shop keeps flammable liquids on hand. How far, at most, may the travel be from that Class B hazard area to a portable fire extinguisher?OSHA, 29 CFR 1910.157. Written to NOCTI HVAC (3045), General Safety
A technician must work on a contactor inside a condensing unit. What does the OSHA electrical rule require of the live parts first?OSHA, 29 CFR 1910.333. Written to NOCTI HVAC (3045), General Safety
How should a heavy compressor be lifted from the floor?US Army TC 9-524, Fundamentals of Machine Tools (1996), chapter 1. Written to NOCTI HVAC (3045), General Safety
Liquid refrigerant can spray from a hose when gauges come off. Which protection does OSHA require against liquid chemical hazards to the eyes?OSHA, 29 CFR 1910.133. Written to NOCTI HVAC (3045), General Safety
Computer Literacy 2
A parts list needs its quantities and prices added up in rows and columns. Which kind of program is made for that?Wikipedia, Spreadsheet. Written to NOCTI HVAC (3045), Computer Literacy
No program on a service laptop can run until one piece of system software has loaded and taken charge of the hardware. What is that software?Wikipedia, Operating system. Written to NOCTI HVAC (3045), Computer Literacy
Employability Skills 2
From the employer's side, what is a job interview for?Wikipedia, Job interview. Written to NOCTI HVAC (3045), Employability Skills
What is a cover letter?Wikipedia, Cover letter. Written to NOCTI HVAC (3045), Employability Skills
Air Conditioning 4
In which state does refrigerant enter the compressor of a working air conditioner?Wikipedia, Vapor-compression refrigeration. Written to NOCTI HVAC (3045), Air Conditioning
What does a cooling tower do in a water-cooled air conditioning plant?Wikipedia, Cooling tower. Written to NOCTI HVAC (3045), Air Conditioning
What is a scroll compressor used for?Wikipedia, Scroll compressor. Written to NOCTI HVAC (3045), Air Conditioning
What is an air handler?Wikipedia, Air handler. Written to NOCTI HVAC (3045), Air Conditioning
Heat Pumps and Electric Heat 5
For the same electric energy, about how much heat can an air source heat pump give compared with an electric resistance heater?Wikipedia, Air source heat pump. Written to NOCTI HVAC (3045), Heat Pumps and Electric Heat
Frost builds on the outdoor coil of a heat pump in winter. How does the defrost cycle clear it?Wikipedia, Air source heat pump, In cold climates. Written to NOCTI HVAC (3045), Heat Pumps and Electric Heat
How do the elements of an electric furnace make heat?Wikipedia, Electric heating. Written to NOCTI HVAC (3045), Heat Pumps and Electric Heat
In heating mode, what does the outdoor coil of an air source heat pump do?Wikipedia, Air source heat pump. Written to NOCTI HVAC (3045), Heat Pumps and Electric Heat
What is the ampacity of a wire?Wikipedia, Ampacity. Written to NOCTI HVAC (3045), Heat Pumps and Electric Heat
Hydronic Systems 3
In a one-pipe hot-water system, how does the water reaching the last radiator compare with the water in the first?US Army FM 3-34.471, Plumbing, Pipe Fitting, and Sewerage (2001), chapter 2. Written to NOCTI HVAC (3045), Hydronic Systems
What does a steam trap let through?Wikipedia, Steam trap. Written to NOCTI HVAC (3045), Hydronic Systems
What does the expansion tank on a closed hot-water heating system do?Wikipedia, Expansion tank. Written to NOCTI HVAC (3045), Hydronic Systems
Forced Air, Gas, and Oil Units 7
A gas furnace has an AFUE of 90 percent. Of every 100 Btu of gas, about how much comes out as useful heat?Wikipedia, Annual fuel utilization efficiency. Written to NOCTI HVAC (3045), Forced Air, Gas, and Oil Units
How does a pressure oil burner prepare fuel oil for burning?Wikipedia, Oil burner. Written to NOCTI HVAC (3045), Forced Air, Gas, and Oil Units
In a forced-air heating system, what does the bonnet above the furnace do?US Army FM 3-34.471, Plumbing, Pipe Fitting, and Sewerage (2001), chapter 2. Written to NOCTI HVAC (3045), Forced Air, Gas, and Oil Units
On a standing-pilot gas appliance, what is the thermocouple in the pilot flame for?Wikipedia, Thermocouple, Gas appliance safety. Written to NOCTI HVAC (3045), Forced Air, Gas, and Oil Units
What is a thermopile (power pile)?Wikipedia, Thermopile. Written to NOCTI HVAC (3045), Forced Air, Gas, and Oil Units
What is the most common fuel for modern furnaces in North America?Wikipedia, Furnace (central heating). Written to NOCTI HVAC (3045), Forced Air, Gas, and Oil Units
Which part does a condensing gas furnace add to take more heat out of the flue gas?Wikipedia, Furnace (central heating), Condensing. Written to NOCTI HVAC (3045), Forced Air, Gas, and Oil Units
Humidity and Air Movement 2
How does an electronic (electrostatic) air cleaner take dust out of the air stream?Wikipedia, Electrostatic precipitator. Written to NOCTI HVAC (3045), Humidity and Air Movement
What does relative humidity compare?US Army correspondence subcourse OD1747, Refrigeration and Air Conditioning I, glossary. Written to NOCTI HVAC (3045), Humidity and Air Movement
Sheet Metal and Ductwork 4
On a forced-air heating plan, how are cold-air return ducts drawn?US Army FM 3-34.471, Plumbing, Pipe Fitting, and Sewerage (2001), chapter 2. Written to NOCTI HVAC (3045), Sheet Metal and Ductwork
Sheet metal thickness is given by gauge number. How does 26 gauge compare with 20 gauge?Wikipedia, Sheet metal. Written to NOCTI HVAC (3045), Sheet Metal and Ductwork
What is galvanized steel duct coated with to keep it from rusting?Wikipedia, Galvanization. Written to NOCTI HVAC (3045), Sheet Metal and Ductwork
Why are turning vanes put inside a square duct elbow?Wikipedia, Duct (flow), Turning vanes. Written to NOCTI HVAC (3045), Sheet Metal and Ductwork
How this list was compiled: Our own questions, written to the competency list of the Job Ready Credential Blueprint for Heating, Ventilation, and Air Conditioning (HVAC) (code 3045, version 01, copyright 2005) that NOCTI publishes at https://www.nocti.org/wp-content/uploads/2020/09/JRHVAC3045.pdf , read 2026-10-13: a written assessment of 200 questions in 3 hours over seventeen areas (Electricity 12%; Soldering, Brazing, and Welding 7%; Pipefitting 3%; Controls 5%; Installation and Service 4%; Related Math and Science 5%; Refrigeration 6%; Refrigerant Recovery 4%; General Safety 6%; Computer Literacy 4%; Employability Skills 3%; Air Conditioning 7%; Heat Pumps and Electric Heat 8%; Hydronic Systems 4%; Forced Air, Gas, and Oil Units 12%; Humidity and Air Movement 3%; Sheet Metal and Ductwork 7%), plus a performance assessment of two jobs. This bank holds 60 in those proportions. The first eleven areas are also the eleven areas of the blueprint for Heating, Ventilation, Air Conditioning, and Refrigeration (HVAC/R), code 3064, a written assessment of 118 questions in 3 hours ( https://www.nocti.org/wp-content/uploads/2020/09/JRHVACR3064.pdf , read the same day). Every rule and definition was read on 2026-10-13 on the public page named under its question: the Army correspondence subcourse OD1747, Refrigeration and Air Conditioning I, US Army FM 3-34.471 (2001) and TC 9-524 (1996) (the copies at archive.org), 40 CFR part 82 on ecfr.gov, OSHA standards on osha.gov, and Wikipedia. The line on Section 608 certification under the questions is from US EPA, Section 608 Technician Certification Requirements, https://www.epa.gov/section608/section-608-technician-certification-requirements , read the same day. Every load, size and reading in a sum is made up for the drill, and each computed answer is arithmetic that was worked twice. Licence: Questions, choices and explanations are original work of this site. OD1747, FM 3-34.471 and TC 9-524 are works of the United States Army approved for public release, and no question or example is copied from them.
How it works
This free NOCTI HVAC practice test is unofficial and is not affiliated with, endorsed by or sponsored by NOCTI. Its 60 questions are our own, sorted by the seventeen areas of blueprint 3045, Heating, Ventilation, and Air Conditioning.
Read the full guide
Seventeen areas and their weights
Electricity and Forced Air, Gas, and Oil Units are 12% each of the written assessment. Heat Pumps and Electric Heat is 8%. Soldering, Brazing, and Welding, Air Conditioning and Sheet Metal and Ductwork are 7% each, and the other eleven areas 3% to 6% each.
HVAC or HVAC/R
NOCTI prints two blueprints. HVAC, code 3045, is 200 questions in 3 hours, a pace at which these 60 take 54 minutes. HVAC/R, code 3064, is 118 questions in 3 hours on the first eleven areas only.
Furnace and air conditioning jobs are shop work
The HVAC performance assessment is a gas furnace start-up and check and an air conditioning job. Neither is practiced on this page.
One ton of refrigeration is 12,000 Btu per hour, so a 3-ton unit moves 36,000.
Superheat is heat added to a vapor above its boiling temperature. Subcooling is a liquid cooled below its condensing temperature.
Questions and answers
How long is the NOCTI HVAC test?
Three hours for the written part of either blueprint. The two HVAC performance jobs add 3 hours and 30 minutes, and the two HVAC/R jobs add 3 hours.
What is on the NOCTI HVAC test?
Seventeen written areas, from Electricity, Controls, Refrigeration and Refrigerant Recovery through General Safety, Computer Literacy and Employability Skills to Heat Pumps, Hydronic Systems, Forced Air, Gas, and Oil Units and Sheet Metal and Ductwork.
Is the NOCTI HVAC test the same as EPA 608?
No. EPA says technicians who maintain, service, repair or dispose of equipment that could release refrigerants must pass an EPA-approved test for Section 608 certification. The NOCTI assessment is a separate credential, and Refrigerant Recovery is 4% of it.
Is there a NOCTI HVAC study guide?
NOCTI's own guide is the blueprint, a free PDF for each code on nocti.org/credentials/blueprints, with the competency list, the area weights and ten sample questions. None of those samples is used on this page.