CRST Study Guide 2026
Everything you need to pass the CRST exam in one place: the exam format, every topic to study, real practice questions with explanations, flashcards, and full-length practice tests. Free, no sign-up needed.
📋 CRST Exam Format at a Glance
📚 CRST Topics to Study (37)
✍️ Sample CRST Questions & Answers
1. A refrigeration system uses a flooded evaporator. What distinguishes it from a dry-expansion evaporator?
In a flooded evaporator, the entire heat exchanger is filled with liquid refrigerant, maximizing heat transfer surface contact.
2. What refrigerant is classified as R-717 and widely used in large industrial refrigeration systems?
R-717 is ammonia (NH3), a natural refrigerant with excellent thermodynamic properties and zero ODP/GWP widely used in industrial cold storage and food processing.
3. What type of oil is required in systems using R-410A refrigerant?
R-410A and other HFC refrigerants require POE oil because it is miscible with HFCs, ensuring adequate lubrication and oil return throughout the system.
4. What is a common cause of refrigeration system failure?
Refrigerant leaks are a very common and critical cause of refrigeration system failure. A loss of refrigerant reduces the system's cooling capacity, increases energy consumption, and can eventually lead to compressor damage due to overheating. Detecting and repairing leaks promptly is vital for system longevity, efficiency, and environmental protection.
5. What is the correct procedure before working on energized refrigeration electrical panels according to NFPA 70E?
NFPA 70E requires an arc flash risk assessment and appropriate arc-rated PPE before working on or near energized electrical equipment.
6. When brazing copper-to-copper refrigeration joints, which brazing alloy family is self-fluxing and most commonly used in the industry?
BCuP (silver-phosphorus-copper) alloys are self-fluxing on copper-to-copper joints because phosphorus acts as its own flux, making them the industry standard for refrigeration brazing.