Connecticut Limited Warm Air, Air Conditioning and Refrigeration System Journeyperson (D-2) Exam Book Package

Prepare for the Connecticut Limited Warm Air, Air Conditioning and Refrigeration System Journeyperson (D-2) examination with a complete collection of technical references and tools covering mechanical systems, fuel gas, refrigeration, warm-air heating, air conditioning, heat pumps, duct sizing, duct construction, ventilation, and liquefied petroleum gas.

The Connecticut D-2 examination evaluates a broad range of practical HVAC knowledge. Candidates should understand natural-gas systems, LP gas installations, refrigeration-cycle principles, heating and cooling equipment, controls, furnaces, heat pumps, duct systems, ventilation, combustion air, chimneys, vents, maintenance, testing, balancing, and mechanical installation requirements.

This D-2 Exam Book Package includes the International Mechanical Code, 2021; NFPA 54 - National Fuel Gas Code Handbook, 2012; Modern Refrigeration and Air Conditioning, 22nd Edition; a Ductulator; HVAC Duct Construction Standards, Metal and Flexible, 2005, 3rd Edition; and NFPA 58 - Liquefied Petroleum Gas Code, 2014.

Each included reference supports a different area of preparation. The International Mechanical Code addresses equipment installation, refrigeration machinery rooms, ventilation, ducts, combustion air, chimneys, vents, piping, and related mechanical requirements. NFPA 54 supports natural-gas preparation, while NFPA 58 addresses liquefied petroleum gas systems.

Modern Refrigeration and Air Conditioning provides technical instruction involving refrigeration, air conditioning, warm-air heating, heat pumps, furnaces, controls, equipment operation, maintenance, and troubleshooting. HVAC Duct Construction Standards covers duct materials, fabrication, reinforcement, fittings, sealing, and supports. The Ductulator supports preparation involving duct sizing, airflow, friction rate, and velocity.

Studying with the correct references helps candidates connect field experience with the terminology used in written examination questions. A journeyperson may know how to install, repair, or maintain an HVAC system, but an examination question may require the candidate to locate a formal requirement, identify a component function, use a sizing table, interpret a diagram, or apply a technical principle.

The D-2 examination is open book, but the testing period is limited. Candidates should become familiar with the books before test day and practice using indexes, tables of contents, chapter headings, definitions, diagrams, and technical tables. Open-book preparation is most effective when candidates know which reference applies to each subject.

This product is a standard D-2 exam book package. It does not include highlighting and tabbing services, online course access, book rental, Application Service, a refundable deposit, or business-formation services.

Exam Details

The Connecticut Limited Warm Air, Air Conditioning and Refrigeration System Journeyperson (D-2) examination contains 60 questions. Candidates are allowed two hours to complete the examination, and a minimum score of 70 percent is required to pass.

The D-2 examination content outline includes the following categories:

• Insulation: 1 question
• Hangers and Supports: 2 questions
• Sound, Vibration and Seismic Control: 1 question
• Heating and Cooling Principles: 5 questions
• Refrigerants and Refrigeration: 8 questions
• Testing, Adjusting and Balancing: 1 question
• Controls: 3 questions
• Machine Room: 1 question
• Air-Conditioning and Heat-Pump Equipment: 5 questions
• Furnaces and Heaters: 4 questions
• Chimneys, Flues and Vents: 2 questions
• Combustion Air: 2 questions
• Fuel Gas Systems: 10 questions
• Ducts: 6 questions
• Chillers: 2 questions
• Ventilation and Exhaust: 3 questions
• Safety: 4 questions

Fuel-gas systems are the largest examination category, accounting for 10 of the 60 questions. Candidates should understand natural-gas piping materials, appliance connections, regulators, system pressure, testing, combustion air, venting, demand, and sizing procedures.

Gas-pipe sizing questions require use of the longest-length method. Candidates should practice determining the longest measured run in the system, selecting the correct sizing table, identifying the connected demand, and applying the selected length consistently when sizing each section.

Refrigerants and refrigeration account for eight questions. Preparation should include the refrigeration cycle, refrigerants, compressors, condensers, evaporators, metering devices, pressure-temperature relationships, charging concepts, operating conditions, maintenance, and troubleshooting.

Ducts account for six questions. Candidates should review duct sizing, airflow, friction rate, velocity, fittings, materials, reinforcement, sealing, supports, construction practices, and air-distribution performance. The included Ductulator and duct-construction standard support study in this area.

Heating and cooling principles and air-conditioning and heat-pump equipment each account for five questions. Candidates should understand heat transfer, sensible and latent heat, airflow, equipment operating sequences, heat-pump cycles, heating processes, cooling processes, and the functions of major system components.

Furnaces and heaters and safety each account for four questions. Controls and ventilation and exhaust each account for three questions. Candidates should also study chillers, chimneys, flues, vents, combustion air, machinery rooms, insulation, testing, balancing, hangers, supports, sound, vibration, and seismic control.

With 120 minutes available for 60 questions, candidates have an average of two minutes per question. This time includes reading the question, identifying the subject, selecting the appropriate reference, locating the supporting information, and choosing an answer.

Open Book Test

The Connecticut D-2 Limited Warm Air, Air Conditioning and Refrigeration System Journeyperson examination is an open-book test. Candidates may bring approved references and permitted tools into the testing center under the applicable examination rules.

The International Mechanical Code supports mechanical questions involving equipment, refrigeration machinery rooms, ventilation, ducts, combustion air, chimneys, vents, piping, and installation requirements. NFPA 54 supports natural-gas questions, while NFPA 58 addresses LP gas systems.

Modern Refrigeration and Air Conditioning supports technical questions involving refrigeration, warm-air heating, air conditioning, heat pumps, furnaces, controls, equipment operation, maintenance, and troubleshooting. HVAC Duct Construction Standards supports duct-fabrication and installation topics, while the Ductulator supports duct-sizing calculations.

Approved books may be highlighted, underlined, annotated, and indexed before the examination. Permanent tabs may be used to identify chapters, definitions, tables, fuel-gas provisions, refrigeration topics, equipment sections, ductwork requirements, and other useful subjects.

Temporary tabs, removable notes, loose papers, and inserted pages are not permitted. Candidates may not write in the references during the examination, and examination questions or answers may not be recorded inside the approved materials.

The books in this standard package are not identified as highlighted or tabbed. Candidates who plan to add permitted highlighting, notes, or permanent tabs should complete that preparation before test day and follow the applicable examination-center rules.

A practical open-book strategy begins by identifying the main topic of the question. Mechanical installation, machinery-room, ventilation, combustion-air, chimney, vent, piping, or duct-system questions may lead to the International Mechanical Code.

Natural-gas piping, appliance, regulator, combustion-air, venting, testing, and sizing questions may lead to NFPA 54. Questions involving LP gas containers, storage, regulators, piping, equipment, or separation requirements may require NFPA 58.

Questions involving refrigeration, air-conditioning equipment, heat pumps, furnaces, controls, chillers, maintenance, or troubleshooting may be supported by Modern Refrigeration and Air Conditioning. Duct-construction questions may require HVAC Duct Construction Standards, while duct-sizing questions may involve the Ductulator.

Candidates should use indexes, tables of contents, chapter headings, definitions, diagrams, and technical tables rather than searching page by page. Reading the complete supporting section is important because notes, exceptions, table headings, and surrounding provisions may affect the correct answer.

Licensing Steps

1. Review the D-2 license scope. Confirm that the Connecticut Limited Warm Air, Air Conditioning and Refrigeration System Journeyperson classification matches the work you intend to perform.
2. Complete the qualifying training pathway. Complete a registered apprenticeship program or an equivalent experience-and-training pathway accepted by Connecticut.
3. Gather supporting documentation. Prepare apprenticeship completion records, classroom records, employment verification, and other materials required for the applicable application route.
4. Complete the journeyperson application. Submit the applicable D-2 application, supporting documentation, and required state fees to the Connecticut Department of Consumer Protection.
5. Receive examination eligibility. Connecticut reviews the applicant’s qualifications and determines whether the candidate may proceed to testing.
6. Prepare for the D-2 examination. Study the approved references, review the examination outline, and practice fuel-gas and duct-sizing problems.
7. Practice open-book navigation. Learn which reference applies to each subject and practice locating definitions, tables, diagrams, and technical requirements under timed conditions.
8. Schedule the examination. Follow the testing provider’s registration and scheduling procedures after receiving eligibility.
9. Complete the D-2 examination. Take the 60-question examination within the two-hour testing period.
10. Complete license-issuance requirements. Submit any remaining examination results, documents, or licensing fees required by Connecticut.

Passing the examination does not automatically issue the D-2 license. Applicants must complete Connecticut’s training, application, examination, documentation, and license-issuance requirements.

State Requirements

The Connecticut D-2 credential is a limited journeyperson license for warm-air heating, air-conditioning, and refrigeration system work. The holder may perform qualifying installation, repair, replacement, maintenance, and alteration work within the scope of the credential.

The classification includes necessary piping used to convey heating or cooling media and associated pumping equipment. It also includes qualifying LP gas supplied by containers, natural-gas piping, approved gas appliances, gas-utilization equipment, and related accessories.

The D-2 license does not include the installation or servicing of oil burners of any size. License holders must remain within the work authorized by the credential and obtain any additional occupational license required for services outside the D-2 scope.

Sheet-metal work is included only as it relates to the limitations of the D-2 credential. The license does not provide unlimited authority to perform unrelated sheet-metal, plumbing, electrical, oil-burner, or other regulated work.

The D-2 license is a journeyperson credential and does not provide independent contracting authority. The holder may perform authorized work only while under the supervision of a contractor licensed for that work.

Applicants qualify by completing a registered apprenticeship program or an equivalent experience-and-training pathway accepted by Connecticut. Supporting documentation may be required to establish classroom education, supervised on-the-job training, apprenticeship completion, or equivalent qualifications.

Applicants with training, experience, or occupational credentials obtained outside Connecticut should follow the applicable state application pathway. Connecticut determines whether submitted qualifications satisfy the requirements for examination eligibility and license issuance.

Candidates should review the D-2 license scope before applying. Connecticut offers several heating, cooling, refrigeration, piping, fuel, and related occupational licenses, and the selected credential should match the work the applicant intends to perform.

Reference Books

• International Mechanical Code, 2021
  This mechanical reference covers equipment installation, refrigeration machinery rooms, ventilation, ducts, combustion air, chimneys, vents, piping, and related mechanical requirements.
• NFPA 54 - National Fuel Gas Code Handbook, 2012
  This fuel-gas reference covers natural-gas piping, sizing, pressure regulation, appliance installation, combustion air, venting, testing, and related safety provisions.
• Modern Refrigeration and Air Conditioning, 22nd Edition
  This technical reference supports preparation involving refrigeration, air conditioning, warm-air heating, heat pumps, controls, equipment, system operation, maintenance, and troubleshooting.
• Ductulator
  This practical tool supports duct-sizing preparation involving airflow, velocity, friction rate, and air-distribution calculations.
• HVAC Duct Construction Standards, Metal and Flexible, 2005, 3rd Edition
  This reference covers duct materials, fabrication, reinforcement, fittings, sealing, supports, and construction requirements for metal and flexible duct systems.
• NFPA 58 - Liquefied Petroleum Gas Code, 2014
  This reference covers LP gas containers, storage, regulators, piping, equipment, installation, separation requirements, and related safety provisions.

Candidates should use the references throughout preparation rather than opening them for the first time on examination day. Repeated study helps build familiarity with chapter locations, index terms, diagrams, technical tables, and the relationship between each examination category and the appropriate source.

Each reference has a different role. Candidates should learn to determine whether a question is primarily mechanical, natural gas, LP gas, refrigeration, equipment, duct construction, or duct sizing before beginning a reference search.

Exam Room Approved Books

The following references and tool are included for D-2 preparation and approved use during the applicable open-book examination:

• International Mechanical Code, 2021
  Use this reference for mechanical equipment, refrigeration machinery rooms, ventilation, ducts, combustion air, chimneys, vents, piping, and installation requirements.
• NFPA 54 - National Fuel Gas Code Handbook, 2012
  Use this reference for natural-gas piping, sizing, appliance installation, pressure regulation, testing, combustion air, and venting.
• Modern Refrigeration and Air Conditioning, 22nd Edition
  Use this reference for refrigeration, warm-air heating, air conditioning, heat pumps, furnaces, controls, equipment, maintenance, and troubleshooting.
• Ductulator
  Use this tool for duct sizing, airflow, velocity, and friction-rate calculations.
• HVAC Duct Construction Standards, Metal and Flexible, 2005, 3rd Edition
  Use this reference for duct construction, fabrication, reinforcement, sealing, fittings, materials, and support requirements.
• NFPA 58 - Liquefied Petroleum Gas Code, 2014
  Use this reference for LP gas containers, regulators, storage, piping, equipment, installation, separation, and safety requirements.

Candidates are responsible for bringing the required references and permitted tools to the examination center. The testing location does not provide each candidate with a complete personal reference set.

The books in this package are standard references and are not identified as highlighted or tabbed. Candidates should complete any permitted book preparation before the examination and follow all applicable testing rules.

Test Information and Study Materials

A productive D-2 study plan should begin with fuel-gas systems and refrigeration because these are the two largest examination categories. Candidates should practice gas-pipe sizing, table navigation, combustion-air review, venting requirements, refrigeration-cycle principles, component functions, and troubleshooting.

Use NFPA 54 to study natural-gas piping, sizing, pressure, appliance installation, regulators, combustion air, testing, and venting. Practice the longest-length sizing method until the process can be completed accurately under timed conditions.

Use NFPA 58 to review LP gas containers, storage, regulators, piping, equipment, separation requirements, and installation safety. Learn how LP gas topics differ from natural-gas provisions and which reference applies to each system.

Use Modern Refrigeration and Air Conditioning to review refrigerants, compressors, condensers, evaporators, metering devices, heat pumps, furnaces, controls, chillers, pressure-temperature relationships, system maintenance, and troubleshooting.

Use the Ductulator and HVAC Duct Construction Standards to study airflow, friction rate, velocity, duct sizing, materials, reinforcement, fittings, sealing, fabrication, and support requirements.

Use the International Mechanical Code for mechanical installation provisions involving equipment, refrigeration machinery rooms, ventilation, combustion air, ducts, chimneys, vents, piping, and related systems.

Timed practice should include identifying the most likely source before beginning a search. Candidates should use the index, chapter headings, definitions, diagrams, and tables to locate the precise supporting information.

Review missed questions carefully. Locate the applicable provision, table, diagram, or technical explanation, determine why the original answer was incorrect, and study related material that may appear in a differently worded examination question.

How 1 Exam Prep Helps You Reach Your Goal

1 Exam Prep helps Connecticut D-2 candidates prepare with an organized collection of examination references and a Ductulator covering the major technical areas associated with the journeyperson test.

Trade-focused review helps candidates connect each examination subject with the correct source. Mechanical questions can be directed to the International Mechanical Code, natural-gas questions to NFPA 54, LP gas questions to NFPA 58, and technical equipment questions to Modern Refrigeration and Air Conditioning.

Practice-oriented preparation helps candidates work through gas-pipe sizing, duct-sizing concepts, technical tables, component questions, and system-operation topics. Researching missed questions in the included references can strengthen both trade knowledge and navigation skills.

Reference familiarity is especially important for an open-book examination. Candidates can practice selecting the correct source, using effective index terms, locating tables, interpreting diagrams, and reviewing complete sections under timed conditions.

The book package also supports a structured study routine. Candidates can divide preparation by examination category, focus on heavily weighted subjects, and direct additional review toward fuel gas, refrigeration, ducts, equipment, controls, safety, or ventilation based on practice results.

No exam book package can guarantee examination eligibility, a passing score, application approval, or license issuance. Consistent study, qualifying training, practical experience, technical understanding, reference familiarity, and effective time management remain important parts of the Connecticut D-2 licensing process.

FAQ Section

What is included in this D-2 Exam Book Package?

The package includes the International Mechanical Code, NFPA 54, Modern Refrigeration and Air Conditioning, a Ductulator, HVAC Duct Construction Standards, and NFPA 58.

Is the Connecticut D-2 examination open book?

Yes. Candidates may bring approved references and permitted tools into the examination center under the applicable testing rules.

How many questions are on the D-2 examination?

The examination contains 60 questions. Candidates have two hours to complete the test and must earn a minimum score of 70 percent.

What are the largest D-2 examination categories?

Fuel-gas systems are the largest category with 10 questions. Refrigerants and refrigeration follow with eight questions, and ducts account for six questions.

Is a Ductulator included?

Yes. A Ductulator is included for duct-sizing, airflow, velocity, and friction-rate preparation.

Does the package include natural-gas and LP gas references?

Yes. NFPA 54 supports natural-gas preparation, and NFPA 58 addresses liquefied petroleum gas systems.

Are the books highlighted and tabbed?

No highlighting or tabbing service is identified as part of this standard D-2 Exam Book Package.

Does this package include online course access?

No. This product is a printed exam book package and does not include online course access.

Is this a rental package?

No. This product is a standard book package and is not identified as a rental.

Does this package include Application Service?

No. Application Service is not included with this standard D-2 Exam Book Package.

Does the D-2 license permit independent contracting?

No. The D-2 credential is a journeyperson license. The holder may perform authorized work only while under the supervision of an appropriately licensed contractor.

Does purchasing this package guarantee a D-2 license?

No. Applicants must meet Connecticut’s qualification requirements, receive examination eligibility, pass the examination, complete the licensing process, and receive state approval.