HVAC/R Red Seal practice test: 25 free exam-style questions with answers

Free HVAC/R Red Seal practice test: 25 questions with answers, explanations and work-area review, online or as a printable PDF. Ontario 313A.

This free Refrigeration and Air Conditioning Mechanic practice test has 25 original multiple-choice questions spread across the work areas of the Red Seal exam, with the answer and an explanation for each question. The real exam has 125 questions in four hours with a 70% pass mark. These are not real exam questions.

HVAC/R practice test PDF: all 25 questions, answers and explanations

HVAC/R Red Seal exam: format, pass mark and how to prepare · HVAC/R Red Seal exam prep app · Prep options compared

313A is Ontario’s trade code for Refrigeration and Air Conditioning Systems Mechanic, not a national Red Seal exam number.

These HVAC/R practice questions follow the official work areas of the Red Seal exam and use the same three question styles as the exam: recall, procedure and critical thinking. Use them as a warm-up before a full timed mock, not as a simulation of the 313A exam.

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Choose one answer per question, then check your score. These 25 questions cover every major work area of the trade but are not a full-length mock or a prediction of passing. Answers stay in this page and are not sent anywhere. Reloading clears your selections.

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Free practice questions with answers

Questions from our public demo, created and reviewed with AI assistance. Answer before opening the explanation, then note the reason for any mistake or uncertain answer. These are independent study exercises, not official exam questions. For workplace tasks, verify the applicable procedures and technical sources.

25 questions across 6 major work activities: Common occupational skills (4) · Routine trade activities (3) · Plans installation (2) · Performs installation (2) · Commissioning (2) · Maintenance and service (12).

All 25 questions, answers and explanations. No account needed.

Question 1 · Common occupational skills

What should the technician do when putting a digital multimeter into service?

Answer question 1A. Identify every energy source, shut down, isolate, apply personal locks and tags, dissipate stored energy and verify zero energy using an approved test.B. Use a meter with the required category and rating, select the correct function and prove it on a known source before and after a zero-energy test.C. Isolate sensitive electronics, disconnect the winding as required, select an appropriate test voltage and discharge the equipment after the test.D. Match the sheet to the exact refrigerant, oil, cleaner or chemical before planning exposure controls.

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Answer: B — Use a meter with the required category and rating, select the correct function and prove it on a known source before and after a zero-energy test.

Correct. For a digital multimeter, use a meter with the required category and rating, select the correct function and prove it on a known source before and after a zero-energy test.

Technical reference for this question

Question 2 · Routine trade activities

Which method follows accepted trade practice when installing a centrifugal refrigeration compressor?

Answer question 2A. Install for unobstructed airflow, proper water distribution, drainage, bleed or conductivity control, freeze protection and service access.B. Maintain exceptionally clean piping, correct alignment and specified oil or magnetic-bearing systems, and commission anti-surge controls.C. Provide specified clearances, prevent discharge-air recirculation, level and support the coil, and establish correct fan rotation and controls.D. Use the specified port orientation, counterflow arrangement, strainers, freeze protection and external supports so piping does not load the plates.

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Answer: B — Maintain exceptionally clean piping, correct alignment and specified oil or magnetic-bearing systems, and commission anti-surge controls.

Correct. For a centrifugal refrigeration compressor, maintain exceptionally clean piping, correct alignment and specified oil or magnetic-bearing systems, and commission anti-surge controls.

Technical reference for this question

Question 3 · Routine trade activities

What is the defining trade function of a direct-expansion evaporator coil?

Answer question 3A. It keeps heat-transfer surfaces supplied with liquid refrigerant while vapour is separated and returned to the compressor.B. It absorbs heat from air while refrigerant boils inside the coil circuits.C. It filters, moves and conditions air through coordinated fan, coil, damper and casing sections.D. It reduces structure-borne vibration by supporting equipment on a compliant element selected for the load.

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Answer: B — It absorbs heat from air while refrigerant boils inside the coil circuits.

Correct. For a direct-expansion evaporator coil, it absorbs heat from air while refrigerant boils inside the coil circuits.

Technical reference for this question

Question 4 · Plans installation

During installation of a low-temperature freeze-stat, which action is required for reliable operation?

Answer question 4A. Locate high and low pressure pickups in representative stable points, connect tubing correctly and set the switch above no-flow effects but below normal flow.B. Use the controller’s specified resistance curve, place the sensor for representative contact and protect leads from moisture and induced noise.C. Pass one intended conductor through the sensor, select a range and threshold below normal load but above leakage or induced current, and wire fail-safe logic as designed.D. Distribute the sensing element across the vulnerable coil face, avoid sharp bends and wire manual reset or sequence action as designed.

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Answer: D — Distribute the sensing element across the vulnerable coil face, avoid sharp bends and wire manual reset or sequence action as designed.

Correct. For a low-temperature freeze-stat, distribute the sensing element across the vulnerable coil face, avoid sharp bends and wire manual reset or sequence action as designed.

Technical reference for this question

Question 5 · Plans installation

Which statement best describes the function of an adjustable time-delay relay?

Answer question 5A. It enforces a minimum compressor off time or restart delay to limit rapid cycling and pressure-related starts.B. It controls compatible AC motor speed and torque by varying output frequency and voltage.C. It delays energizing, de-energizing or contact transfer for a selected period in a control sequence.D. It rotates a damper shaft to position outdoor, return, relief or zone airflow.

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Answer: C — It delays energizing, de-energizing or contact transfer for a selected period in a control sequence.

Correct. For an adjustable time-delay relay, it delays energizing, de-energizing or contact transfer for a selected period in a control sequence.

Technical reference for this question

Question 6 · Performs installation

What inspection should be included when maintaining a portable confined-space atmospheric monitor?

Answer question 6A. Perform the user seal check each time and confirm inspection, storage and change-out records.B. Inspect the cut for roundness, a square face and a removed internal ridge.C. Inspect hooks, latches, chain, brake action and identification, and confirm the load holds during the initial test lift.D. Confirm current calibration and a successful bump test using the specified test gas.

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Answer: D — Confirm current calibration and a successful bump test using the specified test gas.

Correct. For a portable confined-space atmospheric monitor, confirm current calibration and a successful bump test using the specified test gas.

Technical reference for this question

Question 7 · Performs installation

Which test is most relevant to the performance of a total external static-pressure measurement?

Answer question 7A. Add the magnitudes of return negative static and supply positive static as defined and compare with the blower table at measured speed.B. Measure each branch flow or valve differential, adjust iteratively and record final valve positions and pump operating point.C. Measure concentration with a temperature-compensated refractometer suited to the glycol type and verify fluid chemistry by the required test.D. Cross-check every required field against source test sheets and ensure no unresolved deficiency is represented as passed.

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Answer: A — Add the magnitudes of return negative static and supply positive static as defined and compare with the blower table at measured speed.

Correct. For a total external static-pressure measurement, add the magnitudes of return negative static and supply positive static as defined and compare with the blower table at measured speed.

Technical reference for this question

Question 8 · Commissioning

Which check most directly verifies the condition or operation of compressor oil analysis?

Answer question 8A. Compare spectra and overall trend with baseline and correlate peaks with running speed, blade pass and bearing frequencies.B. Check at two or more points when span matters and document as-found, as-left and reference instrument data.C. Record heater current or valve state, coil temperatures, termination time, drainage and fan restart temperature.D. Trend laboratory results against the same oil and compressor baseline and interpret them with filter and operating history.

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Answer: D — Trend laboratory results against the same oil and compressor baseline and interpret them with filter and operating history.

Correct. For compressor oil analysis, trend laboratory results against the same oil and compressor baseline and interpret them with filter and operating history.

Technical reference for this question

Question 9 · Maintenance and service

While troubleshooting, the technician finds that frost extends across the accumulator and liquid is evident at its outlet during stable operation. Which finding best explains the condition?

Answer question 9A. Investigate severe floodback, an undersized accumulator or a damaged internal outlet before restarting the compressor.B. Check outlet valve position, dip-tube connection and receiver orientation before adding charge.C. Check liquid-line pressure drop and receiver or head-pressure control operation instead of using bubbles alone as proof of low charge.D. Reject the cap, make the system safe and replace or assess the relief device and the cause of overpressure.

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Answer: A — Investigate severe floodback, an undersized accumulator or a damaged internal outlet before restarting the compressor.

Correct. For a suction accumulator, investigate severe floodback, an undersized accumulator or a damaged internal outlet before restarting the compressor.

Technical reference for this question

Question 10 · Maintenance and service

During service, head pressure rises when heat reclaim is enabled but the secondary-fluid pump is not running. What is the best interpretation or next action?

Answer question 10A. Disable or bypass reclaim and restore the heat sink or proving interlock before continued operation.B. Verify the economizer metering valve, flash-tank level and injection path before changing compressor capacity settings.C. Check for a leaking liquid solenoid or excessive pressure-control differential before bypassing pump-down.D. Verify the head-pressure control valve ports, setting and receiver-pressure function before adding seasonal charge.

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Answer: A — Disable or bypass reclaim and restore the heat sink or proving interlock before continued operation.

Correct. For a heat-reclaim condenser coil, disable or bypass reclaim and restore the heat sink or proving interlock before continued operation.

Technical reference for this question

Question 11 · Common occupational skills

Which statement best describes the function of a lockout and verification procedure?

Answer question 11A. It controls hazardous energy so work cannot be exposed to unexpected start-up or release.B. It provides selected, fitted and managed respiratory protection when engineering controls alone do not adequately control an identified inhalation hazard.C. It controls ignition, fire and post-work smouldering hazards created by brazing or cutting.D. It supplies controlled heat to bring the joint and filler alloy to brazing temperature.

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Answer: A — It controls hazardous energy so work cannot be exposed to unexpected start-up or release.

Correct. For a lockout and verification procedure, it controls hazardous energy so work cannot be exposed to unexpected start-up or release.

Technical reference for this question

Question 12 · Common occupational skills

A technician observes that a new tube joint has an unexplained restriction immediately beside the cut end. Which response is most technically appropriate?

Answer question 12A. Replace the damaged flare and tighten a newly prepared joint to specification rather than tightening it further.B. Recalculate leg tension and change the rigging because decreasing sling angle increases force in each leg.C. Inspect for an unremoved internal burr or a tube distorted by excessive cutter pressure.D. Remove the regulator from service because seat leakage is causing pressure creep.

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Answer: C — Inspect for an unremoved internal burr or a tube distorted by excessive cutter pressure.

Correct. For a wheel-type copper-tube cutter, inspect for an unremoved internal burr or a tube distorted by excessive cutter pressure.

Technical reference for this question

Question 13 · Common occupational skills

Which check most directly verifies the condition or operation of an oxy-fuel brazing torch setup?

Answer question 13A. Check the identification tag and reject cuts, melted fibres, damaged stitching, chemical attack or other removal criteria.B. Confirm leak-free connections, stable regulator delivery and a neutral or specified flame before heating the joint.C. Confirm calibration status and use a controlled check fixture or calibration service at the required interval.D. Perform a blank-off check and compare remote-system micron response with pump-side pressure during evacuation.

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Answer: B — Confirm leak-free connections, stable regulator delivery and a neutral or specified flame before heating the joint.

Correct. For an oxy-fuel brazing torch setup, confirm leak-free connections, stable regulator delivery and a neutral or specified flame before heating the joint.

Technical reference for this question

Question 14 · Maintenance and service

An operational check shows that the receiver contains liquid but the downstream line receives vapour after a replacement valve was installed. Which decision is justified by this evidence?

Answer question 14A. Check for a stuck plunger, reversed flow, debris or inadequate pressure differential rather than replacing the energized coil automatically.B. Treat the drier as restricted and replace it after making the system safe instead of adding refrigerant.C. Correct bulb contact, position and insulation before adjusting or replacing the valve.D. Check outlet valve position, dip-tube connection and receiver orientation before adding charge.

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Answer: D — Check outlet valve position, dip-tube connection and receiver orientation before adding charge.

Correct. For a liquid receiver, check outlet valve position, dip-tube connection and receiver orientation before adding charge.

Technical reference for this question

Question 15 · Maintenance and service

During service, the liquid line is subcooled upstream but flashes and becomes colder immediately across the filter-drier. What is the best interpretation or next action?

Answer question 15A. Treat the drier as restricted and replace it after making the system safe instead of adding refrigerant.B. Check liquid-line pressure drop and receiver or head-pressure control operation instead of using bubbles alone as proof of low charge.C. Test the branch check valve for leakage or incorrect orientation before changing the control sequence.D. Check actual valve movement, wiring, step calibration and blockage before changing the refrigerant charge.

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Answer: A — Treat the drier as restricted and replace it after making the system safe instead of adding refrigerant.

Correct. For a replaceable-core or sealed liquid-line filter-drier, treat the drier as restricted and replace it after making the system safe instead of adding refrigerant.

Technical reference for this question

Question 16 · Maintenance and service

The service call reports that bubbles appear during a low-ambient condition even though measured subcooling at the condenser outlet is adequate. What should be concluded or checked first?

Answer question 16A. Repair the stem packing or valve and retain a sealing cap; back-seating alone is not a permanent repair.B. Check for a stuck plunger, reversed flow, debris or inadequate pressure differential rather than replacing the energized coil automatically.C. Suspect a partial capillary restriction and verify it rather than adding charge to overcome the restriction.D. Check liquid-line pressure drop and receiver or head-pressure control operation instead of using bubbles alone as proof of low charge.

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Answer: D — Check liquid-line pressure drop and receiver or head-pressure control operation instead of using bubbles alone as proof of low charge.

Correct. For a liquid-line sight glass with moisture indicator, check liquid-line pressure drop and receiver or head-pressure control operation instead of using bubbles alone as proof of low charge.

Technical reference for this question

Question 17 · Maintenance and service

The system has the following condition: the coil is energized and magnetic, but no liquid passes through the valve. What is the best corrective direction?

Answer question 17A. Test the branch check valve for leakage or incorrect orientation before changing the control sequence.B. Reject the cap, make the system safe and replace or assess the relief device and the cause of overpressure.C. Check for a stuck plunger, reversed flow, debris or inadequate pressure differential rather than replacing the energized coil automatically.D. Verify that the installed orifice is not oversized or reversed before changing the charge.

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Answer: C — Check for a stuck plunger, reversed flow, debris or inadequate pressure differential rather than replacing the energized coil automatically.

Correct. For a refrigerant liquid-line solenoid valve, check for a stuck plunger, reversed flow, debris or inadequate pressure differential rather than replacing the energized coil automatically.

Technical reference for this question

Question 18 · Maintenance and service

The measured behaviour is that refrigerant migrates backward through an idle branch and chills the inactive evaporator. What is the most defensible next step?

Answer question 18A. Repair the stem packing or valve and retain a sealing cap; back-seating alone is not a permanent repair.B. Correct bulb contact, position and insulation before adjusting or replacing the valve.C. Test the branch check valve for leakage or incorrect orientation before changing the control sequence.D. Perform an efficiency or valve test because leaking reeds or internal wear can cause re-expansion and low capacity.

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Answer: C — Test the branch check valve for leakage or incorrect orientation before changing the control sequence.

Correct. For a refrigerant check valve, test the branch check valve for leakage or incorrect orientation before changing the control sequence.

Technical reference for this question

Question 19 · Maintenance and service

A technician observes that a back-seated valve stops leaking at the stem until the stem is moved for service. Which response is most technically appropriate?

Answer question 19A. Reject the cap, make the system safe and replace or assess the relief device and the cause of overpressure.B. Check actual valve movement, wiring, step calibration and blockage before changing the refrigerant charge.C. Repair the stem packing or valve and retain a sealing cap; back-seating alone is not a permanent repair.D. Stop it promptly and correct phase sequence before assuming mechanical failure.

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Answer: C — Repair the stem packing or valve and retain a sealing cap; back-seating alone is not a permanent repair.

Correct. For a manual refrigeration service valve, repair the stem packing or valve and retain a sealing cap; back-seating alone is not a permanent repair.

Technical reference for this question

Question 20 · Maintenance and service

While troubleshooting, the technician finds that a technician proposes capping a relief outlet because it has weeped after a pressure event. Which finding best explains the condition?

Answer question 20A. Correct bulb contact, position and insulation before adjusting or replacing the valve.B. Suspect a partial capillary restriction and verify it rather than adding charge to overcome the restriction.C. Reject the cap, make the system safe and replace or assess the relief device and the cause of overpressure.D. Verify the unloading mechanism, oil or hydraulic control and position feedback before adding refrigerant.

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Answer: C — Reject the cap, make the system safe and replace or assess the relief device and the cause of overpressure.

Correct. For a refrigerant pressure-relief valve, reject the cap, make the system safe and replace or assess the relief device and the cause of overpressure.

Technical reference for this question

Question 21 · Maintenance and service

An operational check shows that superheat hunts widely after the bulb was mounted loosely on the bottom of a large horizontal suction line. Which decision is justified by this evidence?

Answer question 21A. Check actual valve movement, wiring, step calibration and blockage before changing the refrigerant charge.B. Correct bulb contact, position and insulation before adjusting or replacing the valve.C. Verify that the installed orifice is not oversized or reversed before changing the charge.D. Move operation away from surge and verify vane, speed or bypass controls and heat-exchanger conditions.

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Answer: B — Correct bulb contact, position and insulation before adjusting or replacing the valve.

Correct. For a thermostatic expansion valve, correct bulb contact, position and insulation before adjusting or replacing the valve.

Technical reference for this question

Question 22 · Maintenance and service

During service, the controller commands the valve open but suction pressure and superheat do not change. What is the best interpretation or next action?

Answer question 22A. Suspect a partial capillary restriction and verify it rather than adding charge to overcome the restriction.B. Check actual valve movement, wiring, step calibration and blockage before changing the refrigerant charge.C. Perform an efficiency or valve test because leaking reeds or internal wear can cause re-expansion and low capacity.D. Correct clearance, wind effects or barriers causing recirculation rather than increasing condenser fan speed blindly.

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Answer: B — Check actual valve movement, wiring, step calibration and blockage before changing the refrigerant charge.

Correct. For an electronic expansion valve, check actual valve movement, wiring, step calibration and blockage before changing the refrigerant charge.

Technical reference for this question

Question 23 · Routine trade activities

Which test is most relevant to the performance of a heat-reclaim condenser coil?

Answer question 23A. Measure reclaimed heat-side flow and temperature rise together with refrigerant condensing pressure and bypass-valve position.B. Measure intermediate pressure, injection superheat, liquid subcooling and capacity response when the economizer is enabled.C. Observe closure, suction pressure decay, compressor stop and off-cycle pressure rebound through several calls.D. Trend condensing pressure, receiver liquid availability and valve pressure differentials as ambient temperature changes.

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Answer: A — Measure reclaimed heat-side flow and temperature rise together with refrigerant condensing pressure and bypass-valve position.

Correct. For a heat-reclaim condenser coil, measure reclaimed heat-side flow and temperature rise together with refrigerant condensing pressure and bypass-valve position.

Technical reference for this question

Question 24 · Maintenance and service

While troubleshooting, the technician finds that a valve moves only a few percent while room temperature swings above and below setpoint. Which finding best explains the condition?

Answer question 24A. Check for oversized valve authority or excessive differential pressure before increasing controller gain.B. Inspect a slipping shaft clamp or disconnected linkage before recalibrating the controller signal.C. Assign a unique address and confirm network integrity before replacing the trunk cable.D. Correct failed-stage detection and enable the designed lag-stage takeover rather than narrowing all stage differentials.

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Answer: A — Check for oversized valve authority or excessive differential pressure before increasing controller gain.

Correct. For a modulating hydronic control valve, check for oversized valve authority or excessive differential pressure before increasing controller gain.

Technical reference for this question

Question 25 · Commissioning

Why is rotating-equipment vibration analysis used in this trade application?

Answer question 25A. It tracks changes in winding-to-ground insulation condition under comparable test conditions.B. It removes scale, sediment or biological fouling that increases approach temperature and pressure drop.C. It preserves the ability to use favourable outdoor air for cooling while maintaining ventilation, pressure and low-limit protection.D. It uses vibration amplitude, frequency and trend to identify developing imbalance, misalignment, looseness or bearing defects.

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Answer: D — It uses vibration amplitude, frequency and trend to identify developing imbalance, misalignment, looseness or bearing defects.

Correct. For rotating-equipment vibration analysis, it uses vibration amplitude, frequency and trend to identify developing imbalance, misalignment, looseness or bearing defects.

Technical reference for this question

0 of 25 answered

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How to use this test

Time yourself at about 1.9 minutes per question, the pace of the real exam (240 minutes for 125 questions). Read the explanation for every wrong choice, then repeat the work area where you missed the most.

Questions about the exam

How many questions are on the Refrigeration and Air Conditioning Mechanic Red Seal exam (Ontario 313A)?

125 multiple-choice questions in four hours, with a 70% pass mark. Each question has four choices and one correct answer, according to the Red Seal exam preparation guide. In Ontario the trade code is 313A.

How long do I have per question?

About 1.9 minutes. The official guide suggests dividing 240 minutes by the number of questions on your exam; 125 questions gives about 1.9 minutes each. Practise at that pace on full mocks.

What score do I need to pass?

70%. The Red Seal exam preparation guide states a 70% pass mark and a four-hour writing time. Confirm the details for your sitting on your exam confirmation.

Where can I get more practice questions?

Start with the free sample questions and self-assessment for your trade on red-seal.ca. For more volume, the HVAC/R Red Seal Exam Prep app has 1,500+ original questions in English and French; the download is free with 50 questions, and one C$19.99 purchase unlocks the rest.

Are these real Red Seal exam questions?

No. They are original questions written to the published exam breakdown. Official exam questions are not published, and the Red Seal Program says it does not endorse any test preparation company or website.

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