Free practice questions for the California CSLB C-38 Refrigeration trade exam — with a written explanation on every answer, in English, Spanish, and Russian.
8 questions, about 4 minutes. No account needed — pick an answer to see whether it's right and read the explanation, the same explanations you get on every question in the full course.
Practice across the full question bank.
Each explanation shows why the correct answer works.
Spend more time on the questions you miss.
Practice under exam-style time pressure before exam day.
Every question tells you why the correct answer is correct and defines the terms it uses — so you learn the rule, not just the answer.
Questions are written from scratch against the official codes and agency publications for this exam — never copied from the real exam.
Every question and explanation is fully translated, with the English exam term kept alongside — not a shallow machine translation.
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The full C-38 Refrigeration course is 500 questions across 5 blocks, and every block is a full mini-exam that mixes these five official sections at CSLB's weights. CSLB calls the percentages approximate.
Exam structure, topics, study areas and official resources.
The C-38 Refrigeration exam is the trade half of a California refrigeration contractor's license; the Law and Business exam is the other half. CSLB's official study guide splits it into five sections — planning and estimating, refrigeration system installation, refrigeration system repair, refrigeration system maintenance, and safety. Practice it in the free sample above: no sign-up, with a written explanation on every question.
Almost a fifth of the exam, split by CSLB into planning refrigeration projects and estimating them. Planning starts with the questions the code makes you answer before you price anything. Does the system need a refrigeration machinery room? Under the 2025 California Mechanical Code (CMC) section 1106.1 it does when the refrigerant in one independent circuit exceeds the amounts in Table 1102.3, when absorption equipment is used, when an A1 system reaches an aggregate 100 compressor horsepower, or when the refrigerant is anything other than Group A1. Which refrigerant is even legal? In California that is a CARB question: 17 CCR §95374 bans refrigerants with a GWP of 150 or more in new refrigeration equipment holding more than 50 pounds in new cold storage warehouses, new retail food facilities and other new facilities. Estimating is arithmetic — loads, labor hours, overhead and markup — and the study guide says some questions require computation and a calculator is provided.
The heaviest section: job site preparation, installing refrigeration equipment, starting systems up, and installing specialty refrigeration systems. CMC chapter 11 governs most of it. Keep an opening at least 36 inches wide and 80 inches high to the compressor and valves (1105.3). Support tubing within 6 feet after the first bend from the compressor, within 2 feet of each later bend, and at least every 15 feet (1109.6). Piping that crosses a passageway runs at least 7.25 feet above the floor (1109.4), and joints must stay exposed for inspection until they have been looked at (1109.8). A system holding more than 6.6 pounds gets stop valves at each compressor's suction and discharge and at the receiver outlet, unless an exception applies (1110.1). Before startup, a field-erected system is pressure-tested and proved tight with dry nitrogen or another nonflammable, nonreactive dried gas — never oxygen or air (1116.2, 1116.3). Above 55 pounds of refrigerant, the installer signs a dated declaration of the test (1116.4).
Troubleshooting refrigeration systems, troubleshooting electrical problems, and repairing them. The electrical side follows the 2025 California Electrical Code, one of the references in CSLB's resource list. The refrigerant side carries federal and state rules. EPA's 40 CFR Part 82 Subpart F covers recovery, evacuation levels and technician certification. Since January 1, 2026, 40 CFR §84.106 makes owners of appliances holding 15 pounds or more of HFC repair leaks above 20 percent a year for commercial refrigeration and 30 percent for industrial process refrigeration, within 30 days. California is faster: CARB's Refrigerant Management Program (17 CCR §95386) gives a certified technician 14 days from detection, and 45 only for documented reasons. Recovered refrigerant has rules too. CMC 1104.8.2 lets recycled refrigerant go back only into systems of the same owner with the same refrigerant and lubricant designation, and anything for another owner must be reclaimed to AHRI 700.
Maintaining refrigeration systems and documenting code compliance — and the documenting is a large part of it. CARB's program sets leak-inspection schedules by system size. A system of 2,000 pounds or more of high-GWP refrigerant that runs year-round inside an enclosed building is inspected monthly unless it has a qualifying automatic leak detection system (17 CCR §95385). The owner keeps the leak, inspection, repair and service records at the facility for at least 5 years (17 CCR §95389), while EPA's §84.106 records run at least three years. The code side matters during maintenance as well. Piping must be identified with the refrigerant type, function and pressure (CMC 1109.10). Stop valves are tagged, with a valve chart under glass near the principal machinery room entrance (1110.5). And the refrigerant you add back has to be legal to reuse, which brings you back to the recover, recycle and reclaim rules.
Personnel safety and job site safety. Refrigeration work puts several hazards in one room: refrigerant that displaces air, high pressure, rotating fans and compressors, and electricity. The CMC handles the room itself. Detectors in a machinery room must trip a visual and audible alarm and the mechanical ventilation at no more than the refrigerant's occupational exposure limit, and the required alarm is manual-reset from inside the room (1106.2.5). Access is limited to authorized personnel, and each door carries a sign saying so (1106.2.4). Cal/OSHA Title 8 handles the people. Under §3314, equipment is locked out or sealed off during repair, tags go on the controls, and the tag attachment must be non-reusable, self-locking and rated for at least 50 pounds. Under §3203, every employer needs a written Injury and Illness Prevention Program, with scheduled inspections to find unsafe conditions.
You take the C-38 exam on a computer at a PSI testing center. CSLB's official Refrigeration (C-38) study guide sets the test policy: closed book with no reference materials, multiple choice with four choices per question and one BEST answer, some computation with a calculator provided, and no penalty for guessing. CSLB's Examinations FAQ gives you 3½ hours for each examination. If you fail, you may retake it after 21 calendar days, inside the 18-month window that starts when your application is accepted. C-38 is not one of the ten exams CSLB offers in Spanish; for other languages you can ask CSLB about an approved translator before you schedule. CSLB does not publish a question count or a passing score for its trade exams, so treat any site quoting one as guessing. Most first-time applicants also sit the CSLB Law and Business exam.
The full LICENA C-38 course is 500 questions across five blocks, and each block is a complete mini-exam that mixes all five official sections at CSLB's weights, so every block reads like test day. At 30 questions a day that is about three weeks: one pass to find what you don't know, a second pass on the sections you missed, then the timed final. Installation is a quarter of the exam, and repair plus maintenance together are another 40 percent, so the refrigerant rules — leak rates, repair clocks, recordkeeping — carry real weight. Read the explanation on every question you miss; the exam rewords facts, and memorizing answer letters buys you nothing. The free EPA 608 practice test covers the federal refrigerant-handling side. If you also work on comfort cooling, the C-20 HVAC practice test covers that license. Pair all of it with CSLB's free official study guide, and treat any resource promising a guaranteed pass as a red flag.
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