Year 2 Exam Study Guide — master what the exam actually tests, concept by concept.
Safety is the first thing assessors look for in any trade professional. This section covers the regulations, procedures, and practices that protect you and those around you on the job. Every answer here reflects a real-world scenario where the wrong choice has consequences.
Plate-frame: efficient liquid-to-refrigerant heat exchanger; common in chiller systems. Knowing what each component does — not just what it is — helps you diagnose failures, specify replacements, and explain your work to inspectors and clients.
Electronic: reaction (glow plug heated, ion source) produces signal when refrigerant vapors pass through. On the job, a solid grasp of this concept means faster decisions, fewer errors, and work that passes inspection the first time.
Oil pressure switch: if oil pressure < differential (typically 20 psi below crankcase), trips motor. Safety regulations exist because the consequences of ignoring them are severe — injury, death, or legal liability. Know these requirements the way you know your own name.
Purge: vent high point receiver; non-condensables rise, are vented with some refrigerant until liquid appears. Safety regulations exist because the consequences of ignoring them are severe — injury, death, or legal liability. Know these requirements the way you know your own name.
Codes and standards define what's legal, what's safe, and what passes inspection. Every trade has its own regulatory framework, and the Red Seal exam tests whether you can navigate and apply those rules to real scenarios.
Evaporative: water spray + dry bulb = efficient cooling; used in hot/dry climates. Memorize this formula and practise substituting values — exam questions often give you three variables and ask you to solve for the fourth.
dry bulb = efficient cooling
Finned evaporators: cold refrigerant cools air blown across fins; standard in air conditioning. Understanding and applying code requirements correctly ensures your installations pass inspection and meet legal obligations in your jurisdiction.
UV dye: inject through service port, dye circulates; leaks glow under UV lamp. On the job, a solid grasp of this concept means faster decisions, fewer errors, and work that passes inspection the first time.
TXV: responsive metering device; capillary: fixed orifice, simple, no moving parts. Being able to compare options and explain the trade-offs is a sign of genuine trade knowledge — and exactly what Red Seal examiners look for.
Receiver: accumulator for liquid, protects compressor from liquid slugging. On the job, a solid grasp of this concept means faster decisions, fewer errors, and work that passes inspection the first time.
Freeze-up: water + refrigerant form ice at expansion point; dehydration prevents. Troubleshooting is a systematic process: identify symptoms, narrow down causes logically, and verify your diagnosis before replacing parts. This logical approach is what examiners want to see.
Calculation questions test your ability to apply trade math to real scenarios. Each formula has a purpose — know what it solves, what the variables represent, and how to check whether your answer makes sense.
Scroll: smooth, continuous compression from spiral overlap; low vibration, efficient. On the job, a solid grasp of this concept means faster decisions, fewer errors, and work that passes inspection the first time.
Air-cooled: hot gas in tubes, aluminum fins increase surface area for air cooling. On the job, a solid grasp of this concept means faster decisions, fewer errors, and work that passes inspection the first time.
Superheat = vapor temp - saturation temp; target 5-15°C; high superheat = starved evaporator. Memorize this formula and practise substituting values — exam questions often give you three variables and ask you to solve for the fourth.
Superheat = vapor temp - saturation temp
P-H diagram: axes are pressure (Y) and enthalpy (X); saturation curve divides liquid/vapor regions. On the job, a solid grasp of this concept means faster decisions, fewer errors, and work that passes inspection the first time.
Oil return: vent lines, proper piping slope (2% min) ensures oil returns to compressor. On the job, a solid grasp of this concept means faster decisions, fewer errors, and work that passes inspection the first time.
High-pressure switch: trips at ~350-400 psi (typical); protects from overpressure. Knowing what each component does — not just what it is — helps you diagnose failures, specify replacements, and explain your work to inspectors and clients.
Low-pressure switch: trips at ~5-10 psi (typical); prevents compressor from running dry. Knowing what each component does — not just what it is — helps you diagnose failures, specify replacements, and explain your work to inspectors and clients.
Non-condensables (air, nitrogen): reduce effective area in condenser, increase pressure. Troubleshooting is a systematic process: identify symptoms, narrow down causes logically, and verify your diagnosis before replacing parts. This logical approach is what examiners want to see.
Understanding the tools, materials, and equipment of your trade — their properties, ratings, and proper applications — is what separates someone who works safely and efficiently from someone who causes problems.
Reciprocating: piston/cylinder, efficient, common in smaller systems (residential, small commercial). On the job, a solid grasp of this concept means faster decisions, fewer errors, and work that passes inspection the first time.
Screw: high capacity, variable displacement, used in large commercial/industrial systems. On the job, a solid grasp of this concept means faster decisions, fewer errors, and work that passes inspection the first time.
Subcooling: liquid temp < saturation temp at measured pressure; typically 5-10°C subcooling desired. On the job, a solid grasp of this concept means faster decisions, fewer errors, and work that passes inspection the first time.
Sat. liquid curve: left side of dome; pure liquid at boiling; increases pressure, increases temp/enthalpy. On the job, a solid grasp of this concept means faster decisions, fewer errors, and work that passes inspection the first time.
Suction gas cooling: cool gas from line passes motor before compression, cooling windings. On the job, a solid grasp of this concept means faster decisions, fewer errors, and work that passes inspection the first time.
R-410A: zero ozone depletion, high pressure requiring new equipment, polyol ester (POE) oil. On the job, a solid grasp of this concept means faster decisions, fewer errors, and work that passes inspection the first time.
R-22: contains chlorine, damages ozone layer; phased out per Montreal Protocol. Troubleshooting is a systematic process: identify symptoms, narrow down causes logically, and verify your diagnosis before replacing parts. This logical approach is what examiners want to see.
Dehydrators: silica gel, molecular sieve absorb water preventing copper plating and acid formation. Safety regulations exist because the consequences of ignoring them are severe — injury, death, or legal liability. Know these requirements the way you know your own name.
How you do the work is just as important as what you do. This section covers the procedures, techniques, and best practices that define journeyperson-level competence in your trade.
Bubble test: apply soap/water solution; escaping refrigerant creates bubbles. On the job, a solid grasp of this concept means faster decisions, fewer errors, and work that passes inspection the first time.
Evacuation: remove air/moisture to prevent ice and acid; standard practice pre-charge. Understanding and applying code requirements correctly ensures your installations pass inspection and meet legal obligations in your jurisdiction.
Split: condenser outdoor, evaporator indoor; allows flexible installation, reduced line set. On the job, a solid grasp of this concept means faster decisions, fewer errors, and work that passes inspection the first time.
Packaged: single unit for small spaces; easier installation than split systems. On the job, a solid grasp of this concept means faster decisions, fewer errors, and work that passes inspection the first time.
All 30 exam concepts from this guide — test your recall before you sit the exam.