🎯 Strategic Study Approach
Not all exam topics are equal. Some appear on 4-5 questions per section, while others may not appear at all. This guide identifies the high-frequency topics that account for 60-70% of exam questions, allowing you to focus your study time where it matters most.
The EPA 608 exam draws from a pool of hundreds of possible questions, but certain topics appear far more frequently than others. Understanding which topics are tested most often allows you to prioritize your study time effectively.
This guide analyzes question patterns across thousands of actual exam experiences to identify the most common topics for each certification type. Use this information alongside our Core, Type 1, Type 2, and Type 3 study guides.
📊 How Exam Questions Are Distributed
Each EPA 608 section contains 25 multiple-choice questions. Question distribution follows a predictable pattern:
| Topic Frequency | Questions Per Section | Study Priority |
|---|---|---|
| High Frequency | 4-6 questions (16-24% of exam) | CRITICAL - Must master |
| Medium Frequency | 2-3 questions (8-12% of exam) | Important - Should study thoroughly |
| Low Frequency | 1 question (4% of exam) | Review - Basic familiarity needed |
⚠️ The 80/20 Rule
80% of exam questions come from just 20% of possible topics. Focus on mastering high-frequency topics first, then expand to medium and low-frequency areas. This approach maximizes your score with minimal study time.
📘 Core Section: Most Common Questions
The Core section tests environmental regulations and refrigerant fundamentals. Here are the topics that appear most frequently:
High-Frequency Core Topics (4-6 Questions Each)
1. Refrigerant Classifications & Environmental Impact
What's tested:
- ODP values for CFCs (1.0), HCFCs (0.05), HFCs (0)
- Which refrigerants are CFCs (R-12, R-500, R-502), HCFCs (R-22, R-123), HFCs (R-134a, R-410A)
- Ozone depletion vs global warming potential
- Montreal Protocol significance (1987)
Common question pattern: "Which refrigerant has the highest ODP?" or "R-22 is classified as a..."
2. Recovery Requirements & Procedures
What's tested:
- Required vacuum levels (10" Hg for R-22, 0 psig for HFCs)
- When recovery is required (ANY amount during service)
- Recovery vs recycling vs reclamation definitions
- Proper recovery equipment operation
Common question pattern: "What vacuum level must be achieved when recovering R-22?" or "Recovery is required when..."
3. Critical EPA Dates & Regulations
What's tested:
- 1987 - Montreal Protocol signed
- 1990 - Clean Air Act Section 608 created
- 1995 - Technician certification required
- 1996 - CFC production banned
- 2020 - R-22 production banned
Common question pattern: "When was the Montreal Protocol signed?" or "CFC production ended in..."
4. Venting Prohibitions & Penalties
What's tested:
- Venting banned July 1, 1992 (except specific exemptions)
- Penalties up to $44,539 per day per violation
- Which refrigerants can NEVER be vented (all except R-718 water, R-744 CO₂, R-729 air)
- De minimis release definition
Common question pattern: "Which refrigerant may be vented to atmosphere?" or "Penalties for venting can be as high as..."
Medium-Frequency Core Topics (2-3 Questions)
- Leak detection methods: Electronic detectors, soap bubbles, dyes, pressure testing
- Cylinder handling: Color codes (gray/yellow for recovery), DOT regulations, filling limits
- System evacuation: 500 microns standard, triple evacuation method
- Refrigerant storage: Proper labeling, cylinder inspection, valve protection
Low-Frequency Core Topics (0-1 Questions)
- Specific heat calculations
- Vapor pressure charts (general concept tested, not detailed reading)
- Historical ozone hole data
- International treaty details beyond Montreal Protocol
🔧 Type 1: Most Common Questions
Type 1 covers small appliances containing 5 pounds or less of refrigerant.
High-Frequency Type 1 Topics
1. 5-Pound Definition & System Identification
What's tested:
- Small appliance = 5 pounds or less refrigerant
- Examples: refrigerators, freezers, window AC units, dehumidifiers
- NOT based on physical size, only refrigerant charge
Common question: "A small appliance is defined as containing how much refrigerant?"
2. Recovery Requirements (0 psig OR 80%)
What's tested:
- Recover to 0 psig OR remove 80% of charge
- Both operating and non-operating equipment
- Self-contained recovery devices required
Common question: "When recovering refrigerant from a small appliance, you must achieve..."
3. Disposal Requirements
What's tested:
- Refrigerant must be recovered before disposal
- Final person in disposal chain responsible for recovery
- Recover at final location, not at collection site
Common question: "Who is responsible for ensuring refrigerant recovery before disposal?"
Medium-Frequency Type 1 Topics
- Flammable refrigerants: R-600a (isobutane), R-290 (propane) safety procedures
- Moisture indicators: Color changes (green = dry, yellow = moisture)
- Hermetic compressors: Sealed unit characteristics, no external shaft
- Piercing valves: Access small systems, proper installation
❄️ Type 2: Most Common Questions
Type 2 covers high-pressure systems including residential AC and commercial refrigeration.
High-Frequency Type 2 Topics
1. Recovery Levels by Refrigerant Type
What's tested:
- R-22: 10 inches Hg vacuum
- HFCs (R-134a, R-410A, R-404A): 0 psig
- Different levels for operating vs non-operating equipment
Common question: "What vacuum must be achieved when recovering R-410A from an operating system?"
2. Leak Repair Thresholds
What's tested:
- Commercial refrigeration: 35% annual leak rate
- Comfort cooling (≥50 lbs): 20% annual leak rate
- 30-day repair requirement after exceeding threshold
- Industrial process: 35% annual leak rate
Common question: "A comfort cooling system with 100 lbs of R-410A must be repaired if it leaks more than..."
3. Vapor vs Liquid Charging
What's tested:
- When to charge vapor (R-22, single-component refrigerants)
- When to charge liquid (R-410A, zeotropic blends during initial charge)
- Why blends must be charged as liquid from cylinder
Common question: "R-410A should be charged into the system as a..."
4. Evacuation Standards
What's tested:
- 500 microns for new installations and major repairs
- Triple evacuation method for moisture removal
- Deep vacuum importance for system longevity
Common question: "When installing a new system, evacuate to..."
Medium-Frequency Type 2 Topics
- A2L refrigerants: R-32, R-454B mildly flammable classification
- Subcooling/superheat: Proper charging verification methods
- Compressor types: Scroll, reciprocating, rotary characteristics
- System components: TXV operation, receiver function, accumulator purpose
🏭 Type 3: Most Common Questions
Type 3 covers low-pressure centrifugal chillers operating below atmospheric pressure.
High-Frequency Type 3 Topics
1. 25 mm Hg Recovery Requirement
What's tested:
- Recover to 25 mm Hg absolute pressure (0 psig)
- Same level for operating and non-operating equipment
- Why chillers operate below atmospheric pressure
Common question: "Refrigerant must be recovered from low-pressure systems to..."
2. R-123 Toxicity & Safety
What's tested:
- R-123 is Class B1 (toxic, non-flammable)
- TLV (Threshold Limit Value) = 50 ppm
- Ventilation requirements for enclosed spaces
- Annual leak testing requirements
Common question: "R-123 is classified as..." or "The TLV for R-123 is..."
3. Purge Units & Air Removal
What's tested:
- Why chillers need purge units (air infiltration at below-atmospheric pressure)
- Proper purge unit operation and monitoring
- Non-condensables affect system efficiency
Common question: "A purge unit is used to remove..." or "Why do low-pressure systems need purge units?"
4. Leak Testing Pressurization Limits
What's tested:
- Maximum 10 psig for pressurizing chillers
- Use nitrogen for leak testing, NOT air
- Controlled pressure addition to prevent damage
Common question: "When leak testing a low-pressure chiller, the maximum test pressure is..."
Medium-Frequency Type 3 Topics
- Rupture discs: Pressure relief for chillers, when they activate
- Vacuum indicators: Reading and interpreting chiller vacuum gauges
- Chiller startup: Proper procedures for initial operation
- Water treatment: Importance for chiller heat exchangers
🎯 Strategic Study Recommendations
Week 1-2: Master High-Frequency Topics
- Create flashcards for recovery requirements, refrigerant classifications, and critical dates
- Take practice tests focusing only on high-frequency topics first
- Review incorrect answers immediately to reinforce learning
- Aim for 90%+ accuracy on high-frequency topics before moving on
Week 2-3: Add Medium-Frequency Topics
- Expand study to medium-frequency areas after mastering high-frequency
- Take full-length practice tests combining high and medium topics
- Identify patterns in questions you miss repeatedly
- Target 80%+ overall accuracy before final week
Final Week: Polish & Review Low-Frequency
- Quick review of low-frequency topics for basic familiarity
- Daily practice tests covering all topics randomly
- Use our cheat sheet for rapid number memorization
- Focus weak areas identified in practice test analytics
🎯 Practice High-Frequency Topics Now
Our practice tests emphasize the most commonly tested topics to maximize your study efficiency
Take Universal Practice Test Take Core Practice Test📈 Question Pattern Recognition
Understanding how questions are phrased helps you recognize correct answers faster:
Common Question Formats
Definition Questions (30% of exam)
Format: "What is the definition of..." or "A small appliance is defined as..."
Strategy: Memorize exact definitions, especially regulatory terms
Scenario Questions (40% of exam)
Format: "When servicing a system containing R-22, you must..." or "If a system leaks 25% annually, you must..."
Strategy: Understand procedures and thresholds, apply them to situations
Identification Questions (20% of exam)
Format: "Which refrigerant is a CFC?" or "R-410A is classified as..."
Strategy: Memorize refrigerant families and characteristics
Comparison Questions (10% of exam)
Format: "What is the difference between recovery and reclamation?" or "Compare R-22 and R-410A recovery requirements"
Strategy: Understand distinctions between similar concepts
💡 Test-Taking Tips for Common Questions
- Look for absolutes: Answers with "always," "never," or "must" are often correct for regulatory questions
- Eliminate obviously wrong answers: Usually 1-2 answers are clearly incorrect
- Watch for trick wording: "CFC" vs "HCFC" - one letter makes a huge difference
- Trust high-frequency knowledge: If you've studied recovery requirements thoroughly, trust your knowledge
- Read carefully: "Which is NOT..." questions require opposite thinking
🎓 Combine with Full Study Guides
This question analysis guide works best when combined with our comprehensive study materials:
- Core Exam Guide - Deep understanding of high-frequency topics
- Type 1 Guide - Small appliance procedures in detail
- Type 2 Guide - High-pressure system mastery
- Type 3 Guide - Low-pressure chiller specifics
- How to Study Guide - Effective learning methods
❓ Frequently Asked Questions
What are the most common EPA 608 test questions?
The most common questions focus on recovery requirements (required vacuum levels for different refrigerants), refrigerant classifications (CFCs vs HCFCs vs HFCs), critical EPA dates (1987, 1996, 2020), leak repair thresholds (20% and 35%), and safety procedures. These topics appear on 60-70% of all exam questions.
How can I identify high-frequency exam topics?
High-frequency topics are those tested 3-5 times per 25-question section. Focus on recovery requirements, refrigerant identification, regulatory dates, leak detection methods, safety classifications, and proper procedures. Our practice tests track which topics appear most often, helping you identify study priorities.
Should I focus only on common questions?
No, but prioritize them. Master high-frequency topics first (accounting for 60-70% of the exam), then study medium-frequency topics (20-30%), and finally review low-frequency areas (5-10%). This approach ensures you can pass (70% required) while optimizing study time.
Do question topics change between exam versions?
The specific questions vary, but high-frequency topics remain consistent across all exam versions. Recovery requirements, refrigerant classifications, and regulatory dates always appear frequently because they're fundamental to Section 608 regulations.
How many questions come from high-frequency topics?
Approximately 15-18 out of 25 questions (60-72%) in each section come from high-frequency topics. Since you need only 18 correct answers (72%) to pass, mastering high-frequency topics alone can get you very close to passing.
Are there topics that never appear on the exam?
Certain advanced technical topics (detailed thermodynamic calculations, specific heat formulas, advanced refrigeration cycle mathematics) rarely or never appear. The EPA 608 exam focuses on practical regulations, safety, and procedures rather than theoretical engineering.
🎯 Next Steps
Use this question analysis to guide your study priorities. Start with high-frequency topics using our comprehensive study guides, then test your knowledge with our practice exams that emphasize commonly tested material.