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

Prepare for the Connecticut Limited Warm Air, Air Conditioning and Refrigeration System Journeyperson (D-2) examination with a focused collection of highlighted and permanently tabbed trade references. This package is designed for candidates who want an organized way to study fuel-gas systems, refrigeration, air conditioning, warm-air heating, heat pumps, ductwork, ventilation, controls, equipment, safety, combustion air, and related mechanical subjects.

The Connecticut D-2 examination requires candidates to combine practical HVAC knowledge with efficient open-book reference navigation. Questions may involve natural-gas piping, LP gas systems, refrigeration-cycle principles, equipment operation, duct sizing, duct construction, controls, furnaces, heat pumps, chillers, ventilation, combustion air, chimneys, vents, testing, balancing, and mechanical installation requirements.

This 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.

All included books are highlighted and permanently tabbed before delivery. Important chapters, definitions, code provisions, fuel-gas subjects, refrigeration topics, equipment information, duct-construction requirements, technical tables, mechanical provisions, and commonly reviewed sections are marked to create a practical starting point for study.

The included highlighting draws attention to useful material, while the permanent tabs provide an organized navigation system for major subjects. Candidates should still review each marked section carefully, learn how the references are organized, and practice locating related information beyond the highlighted passages.

Highlighted and tabbed books are most effective when candidates use them consistently throughout preparation. A practical study session should include identifying the subject, selecting the correct book or tool, locating the relevant section, reading the complete supporting material, and then applying the information to the question.

The D-2 examination is open book, but the testing period is limited. Candidates who are unfamiliar with the references may spend too much time searching. Regular practice with the table of contents, indexes, chapter headings, diagrams, definitions, tables, and permanent tabs can support more efficient exam-room navigation.

This product is a highlighted and tabbed book package. It does not include online course access, book rental, Application Service, a refundable deposit, or business-formation services.

Please allow up to 15 business days for tabbed and highlighted book package orders.

What You Get

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 gas-piping materials, pressure, regulators, appliance connections, testing, combustion air, venting, sizing procedures, and related installation and safety principles.

Gas-pipe sizing preparation should include the longest-length method. Candidates should practice determining the longest measured run, selecting the correct table, identifying connected demand, and applying the chosen length consistently when sizing branches within the system.

Refrigerants and refrigeration account for eight questions. Candidates should review the refrigeration cycle, compressors, condensers, evaporators, metering devices, refrigerants, pressure-temperature relationships, charging concepts, system operation, maintenance, and troubleshooting.

Ducts account for six questions. Preparation should include duct sizing, airflow, friction rate, velocity, fittings, materials, reinforcement, sealing, supports, construction practices, and distribution-system performance. The included Ductulator and HVAC Duct Construction Standards support preparation for these subjects.

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 sequences, heat-pump cycles, heating and cooling operation, and common component functions.

Furnaces and heaters and safety each account for four questions. Controls and ventilation and exhaust each account for three questions. Candidates should also review chimneys, flues, vents, combustion air, chillers, 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 topic, selecting the correct 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 preparation for mechanical equipment, refrigeration machinery rooms, ventilation, ducts, combustion air, chimneys, vents, piping, and related installation requirements. NFPA 54 supports natural-gas questions, while NFPA 58 addresses liquefied petroleum gas systems.

Modern Refrigeration and Air Conditioning supports technical questions involving refrigeration, heating, air conditioning, heat pumps, controls, equipment operation, maintenance, and troubleshooting. HVAC Duct Construction Standards supports duct materials, fabrication, reinforcement, fittings, sealing, and supports. The Ductulator supports duct-sizing calculations.

Approved references 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, ductwork subjects, equipment information, and other useful sections.

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 approved materials.

All included books arrive highlighted and permanently tabbed. Candidates should review every tab before test day, study the highlighted material, and learn the subject connected to each marked section.

A practical open-book strategy begins by identifying the main topic. A mechanical-installation question may lead to the International Mechanical Code. A natural-gas piping, appliance, combustion-air, or venting question may lead to NFPA 54. An LP gas question may require NFPA 58.

Questions involving refrigeration principles, 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 the permanent tabs together with the table of contents, index, chapter headings, definitions, diagrams, and technical tables. Reading the complete supporting section is important because exceptions, notes, table headings, and surrounding provisions may affect the correct answer.

Timed reference practice helps candidates learn when to search a book, when to use the Ductulator, and when to rely on established trade knowledge. It also helps reduce time lost by opening the wrong reference or searching with an ineffective index term.

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 records. Prepare apprenticeship completion documents, classroom records, employment verification, and other materials required for the selected application pathway.
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 examination. Study the highlighted and tabbed books, review the examination outline, and practice locating information under timed conditions.
7. Practice technical calculations. Work with fuel-gas sizing tables, duct-sizing concepts, airflow, velocity, and friction-rate relationships.
8. Schedule the D-2 examination. Follow the testing provider’s registration and scheduling procedures after receiving eligibility.
9. Complete the examination. Take the 60-question D-2 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 for conveying 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 performs authorized work while employed by or under the supervision of a contractor licensed for that work.

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

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

Reference Books

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

The books should be used throughout preparation rather than opened for the first time on examination day. Repeated study helps candidates learn chapter locations, useful index terms, diagram placement, technical-table organization, and the subjects connected with each permanent tab.

The included highlighting and tabbing create an organized framework, but candidates should also practice finding material that is not directly marked. Examination questions may use terminology that requires the index, definitions, cross-references, or surrounding sections.

Exam Room Approved Books

The following highlighted and tabbed references and tool are included for preparation and applicable use during the Connecticut D-2 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, regulators, testing, combustion air, and venting.
• Modern Refrigeration and Air Conditioning, 22nd Edition
  Use this reference for refrigeration, heating, air conditioning, heat pumps, 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, reinforcement, sealing, fittings, materials, fabrication, and supports.
• NFPA 58 - Liquefied Petroleum Gas Code, 2014
  Use this reference for LP gas containers, regulators, storage, piping, equipment, installation, and safety requirements.

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

All included books arrive highlighted and permanently tabbed. Candidates should inspect the materials before examination day and avoid adding loose notes, removable tabs, inserted pages, or other items that may conflict with testing-center requirements.

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 concepts.

Use NFPA 54 to study natural-gas piping, sizing, pressure, appliance installation, regulators, combustion air, testing, and venting. Practice the longest-length 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, 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, machinery rooms, ventilation, combustion air, ducts, chimneys, vents, piping, and related systems.

Timed reference practice should include identifying the likely book before beginning a search. Candidates should use the permanent tabs to reach a major subject and then use the index, chapter headings, definitions, tables, and diagrams to locate the precise supporting information.

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

Candidates should also practice managing difficult questions. Spending too much time on one reference search can reduce the time available for the rest of the examination. A planned approach helps candidates complete all questions before returning to items that require additional review.

How 1 Exam Prep Helps You Reach Your Goal

1 Exam Prep helps Connecticut D-2 candidates begin preparation with an organized collection of highlighted and tabbed examination references and a Ductulator. The package supports study across fuel gas, refrigeration, ductwork, heating and cooling principles, heat pumps, furnaces, controls, ventilation, chillers, combustion air, safety, and mechanical requirements.

Trade-focused review helps candidates connect each examination subject with the correct reference. 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, and equipment questions. Missed questions can be researched in the included references to strengthen both trade knowledge and open-book navigation skills.

The highlighted and tabbed books provide a practical study framework. Highlighting draws attention to useful code provisions and technical explanations, while permanent tabs help candidates move between major chapters, definitions, tables, and examination subjects.

Reference-navigation practice can improve time management during the two-hour examination. Candidates can learn how to identify the topic, select the correct book, choose effective index terms, interpret tables, and review complete sections before selecting an answer.

No highlighted and tabbed book package can guarantee examination eligibility, a passing score, application approval, or license issuance. Consistent study, qualifying training, practical experience, 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 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.

Are all included books highlighted and tabbed?

Yes. All included books are highlighted and permanently tabbed before delivery.

How long should I allow for the order?

Please allow up to 15 business days for tabbed and highlighted book package orders.

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 this package include online course access?

No. This product is a highlighted and tabbed book package and does not include online course access.

Is this a rental package?

No. This product is not identified as a rental package and does not include a refundable book deposit.

Does this package include Application Service?

No. Application Service is not included with this highlighted and tabbed book package.

Does the D-2 license allow independent contracting?

No. The D-2 credential is a journeyperson license. The holder performs authorized work while employed by or 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.