Free Red Seal Refrigeration and Air Conditioning Mechanic examination Practice Questions

Sample Practice Questions

Try these 10 sample questions from the Red Seal Refrigeration and Air Conditioning Mechanic examination practice bank. Each includes the answer and explanation. Continue with the interactive practice above to review the full question set.

1. 1Nadia isolated a refrigeration system, Marta is already working under a personal lock, and Lydia supervises the job. Sofia arrives to help with the work. Following CCOHS individual-lock guidance, whose personal lock must be added for the new worker?

   1. A.Nadia
   2. B.Marta
   3. C.Lydia
   4. D.SofiaCorrect answer: D

   Explanation: CCOHS states, "each individual must place their OWN lock on the system." Sofia is the additional worker on the equipment and therefore places a personal lock. Locks belonging to the isolating electrician, supervisor or other technician do not substitute for hers.

   Reference: CCOHS Lockout/Tag out — 6. Lockout/Tag Out

2. 2After repairing a leak on a federal government-owned refrigeration system using a halocarbon refrigerant, a mechanic chooses the standing dry-nitrogen pressure test described in Environment and Climate Change Canada's code of practice. At 150 psig, what minimum standing time does that standard test specify?

   1. A.15 minutes
   2. B.4 hours
   3. C.8 hours
   4. D.24 hoursCorrect answer: D

   Explanation: The code describes a "standing pressure test at 1034 kPag (150 psig) of dry nitrogen for 24 hours". It separately describes a 15-minute vacuum test and running the unit for 4 to 48 hours before another leak test; those are different steps, not the specified standing pressure-test time.

   Reference: ECCC Environmental Code of Practice for Elimination of Fluorocarbon Emissions — 4.5 System leak repair

3. 3A residential design calculation specifies a 7.0 kW cooling load. Four central air conditioners meet all other project requirements and their listed capacities apply at the design conditions. Following Natural Resources Canada's sizing guidance, which is the lowest available capacity that meets the load?

   1. A.6.0 kW
   2. B.6.5 kW
   3. C.7.0 kWCorrect answer: C
   4. D.7.5 kW

   Explanation: Natural Resources Canada advises, "Select a central air conditioner size or capacity to just meet the design cooling-load calculated." The 6.0 and 6.5 kW choices fall below 7.0 kW; 7.5 kW meets the load but is not the lowest available capacity that does.

   Reference: Natural Resources Canada: Air Conditioning Your Home — Sizing considerations

4. 4A mechanic installs an externally equalized expansion valve on a straight suction line. The layout permits the preferred takeoff point, and the equalizer should sense pressure at the bulb while minimizing the effect of any equalizer leakage on bulb temperature. Which location is preferred?

   1. A.Immediately downstream of the bulbCorrect answer: A
   2. B.Immediately upstream of the bulb
   3. C.Well downstream of the bulb
   4. D.Well upstream of the bulb

   Explanation: The evaporator installation guidance states that the equalizer should sense pressure at the bulb and that this "usually means installing the external equalizer immediately downstream from the bulb." Other locations can be used when the ideal is inaccessible and pressures are essentially the same; upstream leakage can influence bulb temperature.

   Reference: Refplus Industrial Evaporators Installation and Operation Manual — 6.9 External Equalizer Location

5. 5A mechanic checks a charging line for a government-owned halocarbon refrigeration system. Its isolation valve is 10 cm from the service end. Using the ECCC code's recommended placement range, what is the minimum increase in this distance needed to reach the lower end of the range?

   1. A.5 cmCorrect answer: A
   2. B.15 cm
   3. C.20 cm
   4. D.25 cm

   Explanation: The code recommends to "install either self-reseating or isolation valves at 15 to 30 cm" from the end. The lower boundary is 15 cm, so 15 − 10 = 5 cm is the minimum increase. Increasing by 15 cm or 20 cm also enters the range but is not the minimum; 25 cm puts the valve 35 cm from the end, above the range. The wrong values can arise from copying the lower bound, subtracting from the upper bound, or adding the starting distance to the lower bound.

   Reference: ECCC Environmental Code of Practice for Elimination of Fluorocarbon Emissions — 4.9 Charging

6. 6A mechanic monitors the pressure drop across a suction-line burn-out filter after motor damage on a non-freezer refrigeration system. According to Danfoss's filter-drier guidance, what is the stated maximum pressure-drop threshold before replacement?

   1. A.0.15 bar
   2. B.0.25 barCorrect answer: B
   3. C.0.50 bar
   4. D.1.00 bar

   Explanation: Danfoss states, "A suction filter must be replaced before the pressure drop exceeds the following values:" and lists "Refrigeration systems: 0.25 bar". Its separate thresholds for freezing and air-conditioning systems are 0.15 bar and 0.50 bar respectively.

   Reference: Danfoss Fitters Notes: Filter Driers and Sight Glasses — Location in refrigeration system

7. 7Before servicing refrigeration equipment, an authorized mechanic must lock out its electrical supply under the site procedure. Which device does CCOHS identify as an energy-isolating device?

   1. A.Manually operated disconnect switchCorrect answer: A
   2. B.Maintained-contact selector switch
   3. C.Momentary-contact pushbutton switch
   4. D.Thermostat control circuit switch

   Explanation: CCOHS states, "The energy-isolating device can be a manually operated disconnect switch, a circuit breaker, a line valve, or a block" and distinguishes pushbuttons, selection switches and other control-circuit switches from isolation devices. The mechanic still follows the equipment-specific procedure and verifies isolation.

   Reference: CCOHS Lockout/Tag out — What is Lockout/Tag out?

8. 8A trained mechanic is assigned the fire watch for a copper-pipe brazing operation. Under CCOHS hot-work guidance, what is the minimum time the watcher should remain after the hot work stops?

   1. A.15 minutes
   2. B.30 minutes
   3. C.45 minutes
   4. D.60 minutesCorrect answer: D

   Explanation: CCOHS recommends a trained watcher "for at least 60 minutes after work has stopped." This is a minimum in that guidance; the same source notes that longer monitoring may be needed depending on the work and fire hazards.

   Reference: CCOHS Welding - Hot Work — Before performing hot work, what are some general good practices?

9. 9While comparing air-conditioning equipment, a mechanic divides steady-state cooling output in Btu/h by electrical input in watts at a specified temperature. Which rating is being calculated?

   1. A.EERCorrect answer: A
   2. B.SEER
   3. C.HSPF
   4. D.COP

   Explanation: Natural Resources Canada states that the energy efficiency ratio "is determined by dividing the cooling output of the unit, in British thermal units per hour, by the electrical power input, in watts, at a specific temperature." Seasonal and heating ratings use different periods or purposes, and COP uses a consistent energy-unit ratio.

   Reference: Natural Resources Canada: Air Conditioning Your Home — Coming to Terms with Air Conditioners, Other terms

10. 10A mechanic installs a bellows-type pressure switch on a horizontal refrigerant line and wants to reduce oil or sediment collecting in the switch. Where around the line should the pressure connection be taken?

    1. A.On the upper side of the lineCorrect answer: A
    2. B.On the lower side of the line
    3. C.On the left side of the line
    4. D.On the right side of the line

    Explanation: The instructions specify, "Pressure connection of the switch must always be located on the top side of the refrigerant line." This positioning reduces oil, liquid or sediment collecting in the bellows.

    Reference: Danfoss Pressure Switch Installation Instructions — Installation, IMPORTANT mounting instructions