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Practice Core, Type I, Type II, Type III, or a full Universal simulation. Every question includes an explanation and a source trail, and the tool can build follow-up drills from the topics you miss.
The bank contains more than 600 original question variants spanning 155 source-backed concepts. Each concept has four wording/context variants, but a single session will not give you two variants of the same concept. That matters: repeatedly seeing the same fact with the answers merely shuffled is memorization theater, not much of a study tool.
Diagnostic mode samples Core plus the technical section you are targeting. Universal diagnostics sample all four sections. Section and Universal sessions balance their selections across as many topic areas as the session size allows, then pull no more than one variant of any concept family. Universal simulation uses 25 Core, 25 Type I, 25 Type II, and 25 Type III questions. Weak-area mode uses your locally saved topic accuracy to weight the next session toward the concepts you are actually missing.
Your data stays in your browser. The tool stores topic counts, recent misses, and session summaries in localStorage. It does not require an account and does not transmit practice answers to us.
EPA requires certification tests to use a Core group plus the relevant technical group. Appendix D specifies 25 Core questions and 25 questions from each relevant technical group. A Universal test contains 100 questions: 25 Core and 25 each for Type I, Type II, and Type III. Type II, Type III, and Universal testing must be closed-book and proctored in a secure environment.
The federal Appendix D passing score is 70 percent for closed-book Type I, Type II, Type III, and Universal tests, and 84 percent for Type I tests using the mail-in format. Major certifiers may describe their section scoring in whole-question terms. For example, Mainstream Engineering currently publishes an 18-of-25 (72 percent) section benchmark for its Universal administration. This tool shows 18/25 as a practical section benchmark, but you should verify the exact procedure used by your certifying organization.
There is no single federal time limit in Appendix D. The elapsed-time clock in this tool is for pacing awareness only, not an EPA-mandated countdown.
Environmental impacts, Clean Air Act and Montreal Protocol basics, Section 608 rules, substitute refrigerants and oils, refrigeration fundamentals, recover/recycle/reclaim definitions, recovery techniques, dehydration, safety, and shipping.
Review source notesSmall-appliance definitions, recovery requirements, working vs. failed compressors, passive/system-dependent recovery, pressure-temperature identification, access fittings, and small-system safety.
Leak detection, ODS leak-repair rules, recovery methods, evacuation levels by pressure class and charge size, major repairs, pressure-temperature relationships, and high-pressure-system safety.
Low-pressure leak detection, recovery and recharging, 25 mm Hg absolute evacuation, purge concepts, chiller freeze prevention, oil handling, pressure rebound, and machinery-room safety topics.
EPA's public Section 608 test-topic page was last updated December 5, 2025. It includes substitute refrigerants and leak-repair concepts, and EPA has previously stated that its Section 608 test bank includes questions concerning A2L refrigerants. However, the current public topic page does not explicitly say that every 2026 AIM Act Part 84 requirement is now certification-exam content.
That distinction matters. Starting January 1, 2026, 40 CFR 84.106 adds leak-repair requirements for certain appliances with 15 pounds or more of refrigerant containing an HFC or certain HFC substitutes with GWP above 53. But it excludes appliances in the residential and light-commercial air-conditioning and heat-pump subsector. We keep those current field rules in the study notes rather than silently pretending they are confirmed certification-test questions.
The question bank is original TSNET material. It was written against current EPA and eCFR source material, then kept deliberately narrower than some commercial prep manuals where the official public source did not support a precise number. That is why, for example, we do not turn every widely repeated low-pressure-chiller number into a scored item just because it appears on a dozen study sites.
Regulatory material independently reviewed against eCFR content current through September 10, 2026. Question-bank review date: September 14, 2026.
If the weak-area report says the problem is bigger than memorizing a few recovery numbers, that is useful information too. Explore HVAC training, certification, apprenticeships, or appliance repair if Type I work is your focus.
No. EPA states that current Section 608 technician certification credentials do not expire. The Administrator reserves authority to require recertification in the future, but there is no routine federal renewal cycle now.
No. EPA says the Core test must be taken as a proctored exam to count toward Universal certification. Appendix D also says mail-in Type I tests cannot be used toward Universal.
Appendix D specifies 100: 25 Core questions and 25 from each of Type I, Type II, and Type III.
EPA's Appendix D states 70 percent. A 25-question section cannot produce exactly 70 percent using whole questions, and major certifiers such as Mainstream Engineering currently publish 18/25, or 72 percent, as their section benchmark. We label that as a practical simulation benchmark rather than rewriting the federal rule.
No. EPA approves certifying programs, not this TSNET study tool. EPA also states that it does not review or approve training preparatory programs or materials.
