The 313A Red Seal exam has 125 multiple-choice questions, a four-hour writing time and a 70 per cent pass mark, which means 88 correct answers. The questions are spread across six blocks, which the occupational standard calls major work activities. Maintenance and service is the largest with 28 questions, followed by installation (26), commissioning (21), routine trade activities (19), planning installation (18) and common occupational skills (13). The three heaviest blocks, F, D and E, hold 75 of the 125 questions, which is 60 per cent of the exam. The Red Seal Program describes the mix as 20 to 30 per cent knowledge and recall, 50 to 60 per cent procedural and application and 10 to 20 per cent critical thinking, so this is a procedure-heavy exam. A formula sheet and an acronym list are provided at the sitting. The current exam is built on the 2019 standard; a 2024 standard is published, with no date yet for the exam based on it.
01What is the 313A Refrigeration and Air Conditioning Mechanic Red Seal exam?
It is the national certification exam for the trade that the Red Seal Program calls Refrigeration and Air Conditioning Mechanic. Ontario certifies the same trade as Refrigeration and Air Conditioning Systems Mechanic, a compulsory trade, and 313A is Ontario's trade code for it. Other provinces use their own variants of the name. Whichever one you see on a form or a study resource, it is the same exam and the same occupational standard. One trade it is not: Ontario's 313D Residential Air Conditioning Systems Mechanic is a separate, Ontario-only certificate with no Red Seal exam.
The content is set nationally. According to the Red Seal Exam Preparation Guide, tradespeople from across Canada decide what goes into the trade's Red Seal Occupational Standard (RSOS), write and review every exam question, and decide how many questions each section of the standard gets. The exam is then administered by the provincial and territorial apprenticeship and certification authorities. In Ontario that is Skilled Trades Ontario, which issued 445 Certificates of Qualification in the trade in 2024 and runs the apprenticeship over three levels of in-school training totalling 720 hours.
The format is the same as every Red Seal exam: multiple choice, four options (A to D), one correct answer, one mark per question and no penalty for a wrong answer. The 313A exam has 125 questions and the writing time is four hours, about 1.9 minutes per question. The pass mark is 70 per cent. Seventy per cent of 125 is 87.5, so you need 88 correct answers.
One thing to know before you open the standard: the trade is between editions. The Red Seal Program has published a 2024 standard and says new exams based on it are under development, with no date given. Until the program announces one, the exam you book is built on the 2019 standard, and the breakdown below is the one that applies.
The two editions are close. Both have the same six blocks with the same names in the same order. The 2024 edition regroups the tasks from 15 to 17 and moves the national weightings by no more than two points: Block A from 10 to 8 per cent, B from 15 to 16, C from 14 to 13, D unchanged at 21, E unchanged at 17 and F from 23 to 25. Under either edition the same three blocks carry the most weight.
The preparation guide makes one point worth repeating: this is not a test of what your shop does or what your province does. It covers the scope of the trade across Canada at the journeyperson level, from supermarket racks and ammonia plants to residential heat pumps and chillers, so expect questions on equipment you may rarely touch at work.
02What is on the 313A exam?
The Red Seal Program publishes how many questions come from each major work activity. For Refrigeration and Air Conditioning Mechanic the 125 questions break down like this.
| Block | Major work activity | Questions | Share of exam |
|---|---|---|---|
| A | Performs common occupational skills | 13 | 10.4% |
| B | Performs routine trade activities | 19 | 15.2% |
| C | Plans installation | 18 | 14.4% |
| D | Performs installation | 26 | 20.8% |
| E | Performs commissioning | 21 | 16.8% |
| F | Performs maintenance and service | 28 | 22.4% |
| Total | 125 | 100.0% | |
The heaviest block is F, maintenance and service, at 28 questions (22.4 per cent), and installation is close behind at 26. Commissioning is third with 21. Together the three blocks that deal with equipment already on site, from installing it to keeping it running, are 75 questions, or 60 per cent of the exam. The lightest block is A, common occupational skills, at 13 questions, with planning installation (18) and routine trade activities (19) in between. Even the lightest block is worth a tenth of the exam, so none of the six is safe to skip. The shares are worked out from the question counts, and the whole-number percentages the standard prints (10, 15, 14, 21, 17 and 23) match them.
03What does each block cover?
The task names below are the ones the 2019 Red Seal Occupational Standard lists under each major work activity, and the percentages are the standard's own weighting of the tasks within each block, with the question count the Red Seal Program assigns to each task. Questions are written to the sub-tasks. The block titles are the official ones and appear that way on the exam information page.
Block A: Performs common occupational skills (13 questions)
Four tasks and 18 sub-tasks, the most sub-tasks of any block for the fewest questions. Uses tools and equipment is the largest task at 36 per cent of the block, about five questions, and it has ten sub-tasks: hand tools, power tools, brazing and soldering equipment, recovery and recycling equipment, evacuation equipment, charging equipment, diagnostic and measuring equipment, access equipment, rigging, hoisting and lifting equipment, and digital technology. Performs safety-related functions (24 per cent, three questions) covers a safe work environment, lock-out, tag-out and isolation, and PPE and safety equipment. Organizes work (24 per cent, three questions) covers drawings and specifications, documentation and reference material, and planning job tasks. Communication and mentoring is 16 per cent, about two questions.
Block B: Performs routine trade activities (19 questions)
Two tasks. Work site preparation (25 per cent of the block, five questions) covers preparing the site and handling materials and supplies. Performs trade activities carries the other 75 per cent, about 14 questions, over six sub-tasks that are the daily core of the trade: brazing and soldering, leak and pressure tests, evacuating systems, using refrigerants, gases and oils, field wiring of systems, and applying sealants and adhesives. Expect the nitrogen purge, the standing pressure test, the micron gauge and the decay test, refrigerant safety classes and recovery rules, and the line between the mechanic's control and interconnect wiring and the electrician's supply wiring.
Block C: Plans installation (18 questions)
Two tasks with the same four sub-tasks each. Plans installation of HVAC/R systems is 62 per cent of the block, 11 questions: verifying system parameters and requirements, selecting equipment, components and accessories, determining their placement, and material take-off. Plans installation of control systems is 38 per cent, seven questions, with the same four steps applied to controls. This is where load and airflow arithmetic from the formula sheet, psychrometrics, refrigerant line sizing and clearances, and the difference between operating and safety controls are tested.
Block D: Performs installation (26 questions)
Two tasks. Installs HVAC/R systems is 62 per cent of the block, 16 questions, over six sub-tasks: confirming system layout, assembling equipment, components and accessories, placing them, installing fasteners, brackets and hangers, installing piping and tubing, and applying the holding charge. Installs control systems is 38 per cent, ten questions, in two sub-tasks: placing control system components and connecting control systems, which covers 24 V control circuits, transformer sizing, sensor placement, ladder diagrams and communication wiring.
Block E: Performs commissioning (21 questions)
Two tasks. Commissions HVAC/R systems is 61 per cent of the block, 13 questions: pre-start-up checks, start-up, completing the system charge, and setting up primary and secondary system components. Commissions control systems is 39 per cent, eight questions: start-up checks for control systems and verifying or setting operating parameters. That is 21 questions on six sub-tasks, the densest block on the exam. Superheat and subcooling from a gauge set and a P/T chart, charging a blend as liquid, voltage and phase checks, water and air balancing, and proving safety controls all live here.
Block F: Performs maintenance and service (28 questions)
Three tasks. Maintains HVAC/R systems is 30 per cent of the block, eight questions: inspecting systems, predictive and scheduled maintenance, and testing components and accessories. Services HVAC/R systems is 40 per cent, 11 questions, in two sub-tasks: troubleshooting and repairing. Maintains and services control systems is 30 per cent, nine questions: maintenance and inspection, troubleshooting, calibrating operating and safety controls, and repair. The troubleshooting sub-tasks are where the exam's critical thinking questions concentrate: a set of pressures, temperatures and amps, and one cause that fits them.
04What kind of questions are they?
The Red Seal Program describes the 313A question mix as knowledge and recall 20 to 30 per cent, procedural and application 50 to 60 per cent and critical thinking 10 to 20 per cent. On a 125-question exam that is roughly 25 to 38 recall questions, 63 to 75 procedural questions and 13 to 25 critical thinking questions.
That makes it a procedure-heavy exam. More than half the paper asks whether you know how a job is done, and only about a quarter asks you to state a fact. The Red Seal Exam Preparation Guide explains the three types. Knowledge and recall questions check facts related to doing a sub-task, and you can often answer them before you look at the options. Procedural and application questions test whether you know a procedure, and may include calculations or interpreting diagrams. Critical thinking questions check problem-solving: you are given a situation and asked for the cause or the result, and some need you to analyse several pieces of information at once.
For procedural questions the guide says to know all the procedures in the standard, not just the ones you have carried out yourself, and to know every formula and when to use it. In this trade that means the order of recovery, pressure test, evacuation and charge; how superheat and subcooling are measured and which one you charge to on a fixed-orifice system and on a TXV system; which P/T chart column applies to a zeotropic blend; how a low-pressure control is set for pump-down; and how the formula sheet's airflow, water-flow and load formulas are applied to a stated system. For recall, the guide suggests working through the range of variables under each sub-task, the list of components, tools and conditions the wording refers to, and index cards with the term on one side and the meaning on the other. For critical thinking, practise working from a full set of readings to a cause.
The guide also says there are no trick questions, but the incorrect options are not always obvious. When you review practice questions, work out why each wrong option is wrong as well as why the right one is right. On a calculation, the wrong options are usually the results of the common mistakes: the wrong constant, a kelvin difference where the sheet wants degrees Fahrenheit, or gauge pressure where absolute is needed.
05What do you get in the exam room?
The Red Seal Exam Preparation Guide lists what you are provided with: an exam booklet, a diagram booklet if one is required, a pencil and eraser, a calculator if needed, and a bubble sheet to record your answers. It also lists other reference material "if required": an acronym list, math formulas and code book information. Scrap paper is provided too.
For this trade the exam information page is specific about two of them. It publishes the math formulas and the acronym list for Refrigeration and Air Conditioning Mechanic and says both will be provided with the exam sitting. The formula sheet runs to several pages and is imperial: a table of unit abbreviations, a conversion table (kPa to psi, litres to US gallons, metres to feet and so on), a list of constants (12 000 Btuh per ton, 8.33 lb per US gallon, 0.433 psi per foot of water, 1.08 for the specific heat of air, 4.5 for standard air, 3.414 BTU per watt) and then the formulas: Btuh = 4.5 × CFM × ΔH, Btuh = 500 × USGPM × ΔT, Btuh = U × A × ΔT, CFM = velocity × area, Q = CFM × 1.08 × ΔT, psia = psig + 14.7, pressure = height × density, the pulley relationship d1 × rpm1 = d2 × rpm2, coefficient of performance as total heat of rejection over net refrigeration effect, outdoor air percentages, velocity from velocity pressure, and area and volume formulas for circles, cylinders, rectangles and boxes. Practise with the published sheet beside you: it gives you the formula, not when to use it.
The acronym list has more than a hundred entries, from A for ampere to WHMIS, including the ones the questions lean on: CPR, EPR, ORI, ORO and ORD for the regulators, TXV, EEV and LLSV, LPS, OFC and DTFD, PSC and CSIR for motors, SST, P/T and P/E, psia and psig, inHg vac and µm for vacuum. The page does not list code book information for this trade. Anything else you are wondering about, ask your provincial or territorial office what comes with the 313A exam where you write.
You may not bring your own materials or electronics. The guide's rules say no materials, bags, phones, watches or personal calculators in the room, and you use only the pencils, erasers, calculators and scrap paper provided. It adds that your province or territory may have specific rules of its own. More on the day itself is in what to expect on exam day.
06Where should your study time go?
Follow the weights. In order: F (28), D (26), E (21), B (19), C (18) and A (13). Blocks F and D together are 54 of 125 questions, or 43.2 per cent. Add E and you have 75 of 125, which is exactly 60 per cent. The other three blocks, B, C and A, are 50 questions, or 40 per cent.
A sensible split is to give about 60 per cent of your time to the three large blocks, in weight order, and the remaining 40 per cent to the other three. Do not treat the smaller blocks as optional. You need 88 correct answers, and even a perfect score on F, D and E leaves you 13 short, so at least 13 marks have to come from routine trade activities, planning and common occupational skills, and in practice the 50 questions there are where the margin comes from. If ammonia plants, chillers, pneumatic controls or building automation rarely come through your shop, those tasks are exactly what the preparation guide warns about, because the exam covers the trade across Canada rather than the work in front of you.
Within a block, remember how the questions are shared out. Block E puts 21 questions on two tasks and six sub-tasks, so know commissioning in depth: pre-start checks, start-up, charging and set-up, then the control start-up and parameters. Block F puts 11 of its 28 questions on servicing, which is troubleshooting and repair, and splits the rest between maintenance and controls. Block D puts 16 of 26 on the HVAC/R installation itself, from layout to holding charge, and ten on control installation. Block B puts 14 of its 19 questions on the six trade activities, so brazing, testing, evacuation, refrigerant handling and wiring together outweigh site preparation nearly three to one.
Because 50 to 60 per cent of the questions are procedural, most of your time belongs to method rather than terms: work each procedure in the standard through in order, with the formula sheet beside you for the arithmetic, and practise the superheat and subcooling readings until choosing the right P/T column is automatic. Every question is worth one mark and there is no penalty for a wrong answer, so answer everything. For a full method, see how to study for the Red Seal exam.
07How do you use the standard as a checklist?
The Red Seal Occupational Standard for Refrigeration and Air Conditioning Mechanic is public and free. The 2019 edition, the one the current exam is built on, lists 6 major work activities, 15 tasks and 57 sub-tasks, and the preparation guide states plainly that exam questions are based on the sub-tasks and that the standard, not any textbook, is the basis of the exam. Make sure you are reading the 2019 edition rather than the 2024 one: the task numbering differs between them.
To use it as a checklist, go through the 15 tasks and rate yourself on each one using the three levels from the Red Seal self-assessment guide for the trade, which lists every task and sub-task with the number of questions assigned to each major work activity and task: little or no understanding or experience, some experience in limited situations, or fully competent in many situations. Then set your ratings beside the question counts above. A low rating in Block F, worth 28 questions, or Block D, worth 26, is your first priority. A low rating in Block A, worth 13, comes later, but it still goes on the list.
For each weak task, read its sub-tasks in the full standard. Each one lists the skills and knowledge expected and a range of variables, the list of components, tools and conditions the wording refers to: the refrigerant types and safety classes, the metering devices, the control strategies, the test gases, the leak-detection methods. The guide recommends making sure you understand every term used there, because the same terms appear on the exam. Brand names and slang do not. The appendices hold the acronyms, a tools and equipment list and a glossary. All 57 sub-tasks in the 2019 edition are common core, so every one of them is testable.
Official links: the Red Seal Occupational Standard the current exams are based on (the trade page, where the program will announce the exam built on the 2024 standard), the exam information page (the breakdown, the formula sheet and the acronym list) and the self-assessment list.
08Where and how do you write it?
Each province and territory administers the exam itself and decides who is eligible to write it, so booking, fees and rewrite rules depend on where you write. Find your jurisdiction in the guides by province, compare costs in Red Seal exam fees by province, and read what happens if you fail the Red Seal exam before you book. If you are coming to the exam through work experience rather than an apprenticeship, see how to challenge the Red Seal exam.
09Sources
- Red Seal Program: Refrigeration and Air Conditioning Mechanic exam information: 125 questions, the question count for each major work activity, the question mix, and the math formulas and acronym list provided with the exam. This is the breakdown of the current exam.
- Red Seal Program: Refrigeration and Air Conditioning Mechanic trade page and Red Seal Occupational Standard: the 2019 standard the current exam is built on: the 6 major work activities, 15 tasks and 57 sub-tasks, task titles, task weightings within each block and the range of variables; the 2024 standard and the statement that new exams based on it are under development, with no date given.
- Red Seal Exam Preparation Guide: exam format, pass mark, writing time, question types and study methods, exam supplies, exam room rules and the common core rule.
- Red Seal exam self-assessment list: the Self-Assessment Guide for the trade, with the question count per major work activity and task, and the three-level self-rating used in the checklist section.
The question counts were checked against the Red Seal Program's exam information page for this trade on September 24, 2026, and the task lists come from the 2019 Red Seal Occupational Standard, the edition the program says the current exams are based on. If the Red Seal Program changes the breakdown or releases the exam built on the 2024 standard, its page is the final word. If you find one of ours out of date, tell us.
Related: Refrigerant PT chart and superheat / subcooling calculator · All guides · How to study for the Red Seal exam · How many questions are on the Red Seal exam · What happens if you fail the Red Seal exam · 313A Refrigeration and AC practice exam · Free 313A practice questions
10Practice for this exam
TicketPrep 313A practice tests are weighted to the breakdown above, block by block, and every answer is explained, all four options. You can try five sample questions with no account.
Ten free questions per trade, no account: free practice questions. How our questions are written and checked: how our questions are made.