313A Study Guide 2026
Everything you need to pass the 313A 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.
📋 313A Exam Format at a Glance
📚 313A Topics to Study (33)
✍️ Sample 313A Questions & Answers
1. In Canadian HVAC wiring, what voltage is most commonly used for low-voltage control circuits?
24 V AC is the standard low-voltage control circuit voltage in Canadian and North American HVAC systems, provided by a step-down transformer from 120 V or 240 V.
2. Under Canadian ODSHAR regulations, what must technicians do with recovered refrigerant that cannot be reused?
Intentional venting of controlled refrigerants is prohibited in Canada; recovered refrigerant that cannot be reused must be sent to a licensed reclaimer or destruction facility in approved containers.
3. What is the function of the suction accumulator in a refrigeration system?
A suction accumulator is a reservoir installed in the suction line before the compressor. It catches and holds liquid refrigerant and oil that might otherwise enter the compressor, protecting it from liquid slugging. A small metering orifice at the bottom gradually returns oil and small amounts of liquid to the compressor.
4. What symptom would a restricted liquid line filter-drier produce in a refrigeration system?
A restricted filter-drier creates a pressure drop across it, starving the expansion device of liquid — the result is low suction pressure, high superheat, a measurable subcooling temperature drop across the drier, and possibly frost on the drier body where pressure drops sharply.
5. When cutting copper refrigerant tubing, which tool provides the cleanest cut with the least internal deformation?
A wheel-type tubing cutter produces a clean, square cut with only a small internal burr that is easily removed by reaming, while saws leave rough edges and metal filings.
6. What is the difference between a fin-and-tube evaporator and a plate evaporator?
Fin-and-tube evaporators use copper or aluminium tubes with aluminium fins pressed onto them to increase surface area for air-to-refrigerant heat exchange. Plate evaporators use corrugated stainless steel plates to create channels for refrigerant and the fluid being cooled, offering high efficiency in compact liquid-cooling applications.