Based on the Red Seal 313A standard & CSA B52 (Mechanical Refrigeration Code)
About the certification
In Ontario, Refrigeration and Air Conditioning Systems Mechanic is trade code 313A (not to be confused with 313D, the shorter, non-Red-Seal Residential Air Conditioning Systems Mechanic branch). The written Certificate of Qualification (C of Q) exam is administered by Skilled Trades Ontario. 313A is a Red Seal trade, so Ontario's certifying exam is the interprovincial Red Seal Refrigeration and Air Conditioning Mechanic exam — passing it earns both your C of Q and the Red Seal endorsement.
The Red Seal exam has 125 multiple-choice questions with a 70% pass mark, and candidates are generally allotted up to about four hours. Questions are built from the Red Seal Occupational Standard for the trade; day-to-day work is governed by CSA B52, Canada's Mechanical Refrigeration Code, and Skilled Trades Ontario's Apprenticeship Training Standard.
ExamHub's free 313A practice quiz has 150 original questions across six topic areas that mirror the official exam weighting, with an explanation and a cited source for every answer. It is unofficial study practice — always confirm current requirements with Skilled Trades Ontario and the latest code, including the current CSA B52 provisions covering A2L refrigerants like R-32 and R-454B.
What's covered
Categories map to the Red Seal exam's Major Work Activity blocks, with maintenance & service and installation the most heavily weighted — just as they are on the real exam.
Try a few
Five questions pulled from the full bank, with the answer shown — use the quiz above for the real timed experience.
Why: A compound gauge cannot resolve anything below roughly 25 inches of mercury, which still leaves plenty of moisture behind. A micron gauge reads the deep vacuum range directly, so a technician can confirm 500 microns and — more usefully — watch whether the vacuum holds once the pump is valved off.
Why: Measure suction pressure, convert it to saturation temperature, and subtract that from the measured line temperature. Any superheat proves the refrigerant has fully boiled off; too little risks liquid reaching the compressor, and too much means the evaporator is being starved.
Why: R-32 and R-454B are A2L, lower-GWP refrigerants now standard in new residential and light commercial equipment. R-717 is ammonia and R-744 is CO2, both used in commercial refrigeration but not in residential comfort cooling; R-22, R-12, R-11 and R-113 are long phased out.
Why: Less refrigerant reaching the evaporator means it boils off early, so superheat climbs and suction pressure falls; subcooling falls too. Once coil temperature drops below freezing the condensate turns to ice, which restricts airflow and makes everything worse.
Why: Recovery simply removes refrigerant into a cylinder. Recycling cleans it, usually by filtering and drying, for reuse in the same owner's equipment. Reclaiming reprocesses it at a licensed facility to meet AHRI 700 purity so it can legally be resold as equivalent to new.
FAQ
The interprovincial Red Seal Refrigeration and Air Conditioning Mechanic exam has 125 multiple-choice questions. ExamHub's practice bank has 150 original questions, and the timed 'Test Me' mode draws a 100-question practice test.
The Red Seal exam pass mark is 70%. On the real 125-question exam that's 88 correct; ExamHub uses the same 70% threshold.
Red Seal exams are generally allotted up to about 4 hours. ExamHub's Test Me mode gives you up to 4 hours, which is far more than most people need.
The Red Seal exam weighting is split across six blocks: common occupational skills, routine trade activities (tools & instruments), plans installation, performs installation, performs commissioning, and maintenance and service — the largest single block.
No. 313A (Refrigeration and Air Conditioning Systems Mechanic) is the full Red Seal trade covering residential, commercial, and industrial systems. 313D (Residential Air Conditioning Systems Mechanic) is a separate, shorter, non-Red-Seal branch limited to residential air conditioning. This quiz covers the 313A Red Seal scope.
No. These are original questions written by ExamHub from the Red Seal Occupational Standard, Skilled Trades Ontario's 313A Apprenticeship Training Standard, and CSA B52. They cover the same topics but aren't copies of any real exam. Always verify against current code before relying on any value in the field.