Oil Heat System Technician Red Seal (312A) Exam Prep
750 practice questions across 6 full-length tests
Matched to the Oil Heat System Technician NOA
Detailed answer explanations — not just an answer key
Canadian exam simulation in every test
The Oil Heat System Technician Red Seal exam has 100 multiple-choice questions. The questions are split across six Major Work Activities (MWAs) from the Oil Heat System Technician National Occupational Analysis. The table below shows how the questions are split. Our book follows the same structure so your study time matches the real exam.
| Knowledge Domain / Major Work Activity | Number of Questions |
|---|---|
| A — Performs common occupational skills B — Installs, services and decommissions oil storage tanks and supply systems C — Installs and services burners, ignition and combustion systems D — Installs and services boilers, furnaces and water heaters E — Installs and services venting and air supply systems F — Installs and services controls, wiring and accessories Total | 13 20 22 20 13 12 100 |
Source: Red Seal Occupational Standard for Oil Heat System Technician (red-seal.ca). This is a study aid. Red Seal Training Academy is not affiliated with the Red Seal Program.
Which Path Are You On?
Apprentice writing the IP exam
You have finished your technical training and are booked to write the Interprovincial (IP) exam. Use our 6 full-length tests to pace yourself, find weak areas, and walk in ready.
Trade Qualifier / Challenger
You have around 7,200 hours of documented work experience but did not go through the apprenticeship schooling. You plan to challenge the Red Seal exam through your provincial Trade Equivalency Assessment. Our book covers the full NOA so you can close the gaps before exam day.
Rewriting after a previous attempt
If your last attempt did not go the way you wanted, use our detailed answer explanations to fix the knowledge gaps, not just memorize answers. Every question in the book has a written explanation.
Try 3 Free Sample Questions
One question of each type you will see on the real exam. Scroll to see the answer and explanation.
What is the typical operating oil pressure of a standard high-pressure gun-type oil burner?
A. 50 psi
B. 100 psi
C. 140 psi
D. 200 psi
Answer: C
Explanation:
Most modern residential high-pressure gun-type oil burners operate at 140 psi (100 psi was the standard on older burners). The higher pressure produces finer atomization of the fuel oil, which improves combustion efficiency and reduces soot. Always confirm the exact setting on the burner nameplate or nozzle chart.
What is the correct sequence for purging air from an oil line after installing a new tank?
A. Open the bleed port, start the burner, let oil run until clear, close the port
B. Run the burner for 30 minutes then bleed
C. Bleed with the burner off, using a hand pump or gravity flow
D. Only required on two-pipe systems
Answer: A
Explanation:
On a single-pipe system, the standard purge is: open the bleed port on the fuel pump, start the burner so the fuel pump draws oil, catch the discharge in a container, and continue until the oil flows clear and free of air bubbles. Then close the port while the pump is still running to avoid pulling air back in. Two-pipe systems self-bleed through the return line.
An oil furnace short-cycles on high-limit and the flame appears yellow and smoky. Stack temperature is high. Draft is correct. Oil pressure is at spec. What is the most likely cause?
A. Undersized nozzle
B. Worn or incorrect nozzle, or dirty heat exchanger
C. Low oil pressure
D. Excess combustion air
Answer: B
Explanation:
Yellow smoky flame with high stack temperature points to poor atomization (worn nozzle or wrong size/angle) or a fouled heat exchanger that can’t transfer heat. The high limit trips because the stack is carrying heat the heat exchanger should be absorbing. Draft and oil pressure are confirmed correct. The fix: replace the nozzle with the correct size and pattern, inspect and clean the heat exchanger.
Our book has 750 questions like these, with an explanation for every one.
Oil Heat System Technician Red Seal Exam — Frequently Asked Questions
What is the Red Seal Oil Heat System Technician exam?
The Red Seal Oil Heat System Technician exam is the national trade certification exam for oil heat techs in Canada. It tests the knowledge listed in the OHST Red Seal Occupational Standard. When you pass, you receive the Red Seal endorsement on your provincial Certificate of Qualification. This lets you work as a journeyperson OHST in any province or territory in Canada without re-certifying.
How many questions are on the OHST 312A exam?
The exam has 100 multiple-choice questions. Each question has one correct answer out of four options. The questions are split across the six Major Work Activities in the National Occupational Analysis.
What is the pass mark?
The pass mark is 70%. You need to answer at least 70 out of 100 questions correctly to pass.
How long do I get to write the exam?
You are given 4 hours to write the exam. Most candidates finish before the time is up.
Can I challenge the exam without an apprenticeship?
Yes, in most provinces. You need to show around 7,200 hours of documented work experience in the trade through your provincial apprenticeship body. This route is called Trade Qualifier (TQ) or Trade Equivalency Assessment. Check the rules in your province before you apply.
Do I need a separate OBT2 or CSA B139 certification to work as an OHST?
Yes. Most Canadian jurisdictions require a CSA B139 certified technician card to install and service oil-fired equipment. The Red Seal Oil Heat System Technician designation is recognized as meeting CSA B139 technician requirements in most provinces, but check with your provincial authority having jurisdiction (AHJ).