313A Red Seal — Refrigeration & AC Mechanic

About the 313A Red Seal Exam — Refrigeration & AC Mechanic

The 313A Refrigeration and Air Conditioning Mechanic Red Seal exam is Canada's national certification for technicians who install, maintain, and service commercial and industrial refrigeration systems, HVAC equipment, and process cooling. Refrigeration mechanics with Red Seal status are in high demand across food processing, cold storage, commercial real estate, and industrial facilities.

The exam consists of 125 multiple-choice questions based on the 2023 Red Seal Occupational Standard (RSOS), requiring a minimum score of 70%. Exam time is 4 hours.

Official 313A Exam Breakdown (red-seal.ca)

Red Seal publishes how the 125 questions on the real 313A exam are distributed across its Major Work Activities:

• A — Performs common occupational skills — 13 questions (10%)
• B — Performs routine trade activities — 19 questions (15%)
• C — Plans installation — 18 questions (14%)
• D — Performs installation — 26 questions (21%)
• E — Performs commissioning — 21 questions (17%)
• F — Performs maintenance and service — 28 questions (22%)

Every question is four-option multiple choice with one correct answer, the writing time is four hours and the pass mark is 70%. Source: 313A exam information, red-seal.ca. Exams are periodically rewritten to updated occupational standards, so check that page before you book.

What this question bank covers

These are the topic areas in this practice bank and what each one covers. The real 313A exam has 125 questions and a four-hour writing time. How those questions are distributed across the official blocks is published by Red Seal — see the 313A exam information page.

• Refrigeration Theory & Cycle Analysis — The foundation of the exam. Vapour-compression cycle (evaporation, compression, condensation, expansion), P-H diagrams (Mollier charts), subcooling and superheat calculations, COP and system efficiency. You must be able to read a P-H diagram and diagnose system performance from it.
• Refrigerants & Environmental Regulations — Refrigerant properties (R-404A, R-410A, R-134a, R-744 CO₂, R-290 propane, low-GWP alternatives), HCFC phase-out schedules, Environment and Climate Change Canada (ECCC) regulations, refrigerant recovery and handling (TSSA/CSA B52), and leak detection methods.
• Compressors — Reciprocating, scroll, screw, and centrifugal compressor operation, capacity control, valve diagnostics, oil management, and failure analysis. Suction and discharge pressure relationships.
• Electrical Controls & Automation — Ladder logic, sequencing controls, solid-state relays, VFDs for compressors and fans, DDC/BAS system integration, pressure and temperature controllers, and safety control circuit testing.
• Condensers, Evaporators & Heat Transfer — Air-cooled and water-cooled condensers, cooling tower operation, evaporative condensers, direct-expansion and flooded evaporator circuits, defrost methods (electric, hot gas, off-cycle).
• Piping, System Installation & Safety — CSA B52 Mechanical Refrigeration Code, pipe sizing, pressure testing, nitrogen purging, refrigerant charge verification, and machine room requirements.

Exam Strategy for 313A

Master the P-H diagram. Pressure-enthalpy diagrams appear in multiple 313A questions. Practice plotting a complete cycle, identifying subcooling and superheat zones, and diagnosing abnormal conditions (high discharge temp, liquid slugging, flash gas in the liquid line).

Know the current refrigerants. Questions on low-GWP refrigerants (R-32, R-454B, R-744) have increased with each RSOS revision. Understand their flammability classification (A2L), pressure behaviour, and oil compatibility.

Electrical controls are heavily tested. The 313A has increased its electrical/controls weighting significantly. Expect ladder logic diagrams, VFD parameter questions, and DDC setpoint questions.

How to Use This Practice Tool

This tool includes 115 questions covering all 313A topic blocks with full answer explanations. Filter by topic to drill refrigeration cycle calculations and refrigerant properties — the two areas where most candidates lose marks. Use Mock Exam Mode to practice under timed conditions.

Related reading: How to Pass the 313A Red Seal Exam | 313A Salary Guide | 313A Career Guide