Work through HVAC questions on fan airflow, duct insulation, equipment installation and superheat. Read the explanation behind each answer before moving to the next question.
According to the California Building Code (CBC), a residential heating system must be capable of maintaining a minimum temperature of _______°F at a height of _______ feet above the floor in all habitable rooms.
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Work through 20 original practice questions on fan speed and airflow, duct insulation, combustion air and HVAC installation. Check vent and condensate slopes, equipment access, thermostat connections and troubleshooting clues such as superheat and pressure differences. Your result groups the sample by published CSLB topic area, helping you choose what to review next.
The C-20 HVAC Contractor exam draws from these published CSLB topic areas. The percentages show approximate exam weights; your sample result groups answers by the same areas.
Topic names and weights follow CSLB C-20 HVAC Contractor study guides; your practice here uses original Test2Pro questions grouped by those areas.
Installation decisions and service diagnosis meet in this HVAC sample. You might calculate a fan speed, check an attic access requirement, then interpret a refrigerant pressure reading. Questions are grouped by CSLB topic areas, including Fabrication, Installation, and Startup, the largest part of the published outline. Use your result to find gaps beyond the work you do most often; it does not predict whether you will pass. Full prep adds the complete question bank, saved history and readiness tracking.
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CSLB provides a free C-20 study-guide PDF with the exam outline, reference materials and three sample questions. Open it through the study-guide link on this page. Test2Pro's free sample is an online test with 20 original questions and instant explanations; we do not offer it as a downloadable PDF.
The guide lists the 2025 Building Energy Efficiency Standards (Title 24 energy rules), the 2025 California Mechanical, Plumbing, Building, Electrical and Energy Codes, ACCA manuals such as Manual J (load calculation), Manual D (duct design) and Manual S (equipment selection), the ASHRAE Handbooks, SMACNA duct construction standards, three HVACR textbooks and the Cal/OSHA safety orders. The exam is closed-book, so these are study references.
Service experience is useful, but the outline also covers design and installation. Fabrication, Installation, and Startup is the largest area of the outline. CSLB gives you 3-1/2 hours for a closed-book exam. Each question has four choices and one best answer, and there is no penalty for guessing. Review the installation topics alongside the diagnostics you use on service calls.
No. CSLB does not currently list C-20 among its Spanish-language exams; Law & Business is available in Spanish. If no translated exam is available, CSLB may allow a translator you choose, approved in advance. You can still study in your language: the Test2Pro site works in English, Spanish, Chinese, and Russian, and practice questions can be shown in 8 languages.
The guide includes load and psychrometric calculations in the exam outline, and its sample questions include a ventilation calculation using air changes and airflow. This free test includes a fan-speed calculation relating CFM to RPM. CSLB provides a calculator for computation questions. Use the guide for the broader math scope; this sample does not cover every calculation type.
Yes. Questions address zero superheat in a system with a thermostatic expansion valve, where to take measurements for total superheat, a small difference between suction and discharge pressures, and a partially blocked air filter. The explanations help you review the diagnostic reasoning behind each answer.
Sort missed questions into calculations, installation requirements and diagnosis. Start with the group that needs the most review, then use saved practice history to see whether those mistakes recur.
Topic names and weights follow CSLB study guides; practice questions are original Test2Pro content.
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