Page 1 of 107
Ontario Gas Technician 1 (G1) Certification Exam ACTUAL
EXAM COMPLETE QUESTIONS AND CORRECT ANSWERS
LATEST UPDATE THIS YEAR
Ontario Gas Technician 1 (G1) Certification Exam
The Gas Technician 1 (G1) certification in Ontario is the highest-level gas license under the Technical
Standards and Safety Authority (TSSA). It authorizes technicians to work on all gas-fired equipment
(unlimited BTU input), including industrial and commercial systems.
1. Codes, Acts, and Regulations
• CSA B149.1 Natural Gas and Propane Installation Code (primary code)
• Ontario Technical Standards & Safety Act (TSSA regulations)
• Fuel Safety Programs and enforcement requirements
• Duties of certified G1 technicians vs G2/G3
2. Combustion Theory & Gas Properties
• Principles of complete vs incomplete combustion
• Air-to-fuel ratios and excess air calculations
• Properties of natural gas and propane (BTU values, density)
• Flame characteristics and combustion efficiency
• Carbon monoxide formation and hazards
3. Gas Piping Systems (Advanced)
• Pipe sizing for high BTU commercial systems
• Pressure drop calculations
• Materials: steel, copper, CSST
• Regulators, meters, and pressure controls
• Leak detection and testing procedures
4. Industrial & Commercial Appliances
• Boilers (fire-tube, water-tube)
• Make-up air units (MAUs)
• Rooftop units (RTUs)
• Process burners and ovens
• Infrared heaters and unit heaters
5. Controls & Electrical Systems
• Advanced control circuits (relay logic, PLC basics)
• Flame safeguard systems
• Safety interlocks and limit controls
• Wiring diagrams and troubleshooting
6. Venting & Air Supply
• Venting categories (I, II, III, IV)
• Draft, vent connectors, chimney systems
• Combustion air requirements (mechanical & natural)
• Negative pressure and backdrafting
7. Installation & Commissioning
• Equipment installation procedures
• Start-up and commissioning checks
• Gas pressure adjustments and manifold settings
• Combustion analysis (O₂, CO₂, CO readings)
8. Troubleshooting & Diagnostics
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• Systematic fault-finding methods
• Burner ignition failures
• Flame failure issues
• Control circuit faults
• Pressure and airflow problems
9. Safety & Hazard Management
• Carbon monoxide hazards
• Explosion risks and prevention
• Lockout/tagout procedures
• Confined space awareness
• Emergency response procedures
10. Maintenance & Inspection
• Preventive maintenance schedules
• Heat exchanger inspection
• Vent system inspection
• Efficiency testing and adjustments
1.A technician observes yellow-tipped flames in a commercial boiler burner during operation; what is
the most likely cause requiring correction?
A. Excess primary air
B. Insufficient combustion air
C. High gas pressure
D. Low gas pressure
Answer: B
Rationale: Yellow flames indicate incomplete combustion due to insufficient air supply.
2.
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During commissioning, manifold gas pressure is lower than specified by the manufacturer; what is the
correct first step?
A. Replace burner
B. Adjust regulator or supply pressure
C. Increase air supply
D. Shut down permanently
Answer: B
Rationale: Proper manifold pressure is essential for correct combustion.
3.
A rooftop unit repeatedly locks out on flame failure despite ignition spark presence; what is the most
likely issue?
A. High airflow
B. Faulty flame sensor
C. Excess gas pressure
D. Blocked vent
Answer: B
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4.
A combustion analyzer shows elevated CO levels during boiler operation; what should be done
immediately?
A. Increase gas input
B. Shut down and correct combustion
C. Ignore if stable
D. Add ventilation
Answer: B
5.
A gas piping system serving multiple appliances shows excessive pressure drop; what is the likely cause?
A. Oversized piping
B. Undersized piping
C. High gas quality
D. Low appliance demand
Answer: B
Ontario Gas Technician 1 (G1) Certification Exam ACTUAL
EXAM COMPLETE QUESTIONS AND CORRECT ANSWERS
LATEST UPDATE THIS YEAR
Ontario Gas Technician 1 (G1) Certification Exam
The Gas Technician 1 (G1) certification in Ontario is the highest-level gas license under the Technical
Standards and Safety Authority (TSSA). It authorizes technicians to work on all gas-fired equipment
(unlimited BTU input), including industrial and commercial systems.
1. Codes, Acts, and Regulations
• CSA B149.1 Natural Gas and Propane Installation Code (primary code)
• Ontario Technical Standards & Safety Act (TSSA regulations)
• Fuel Safety Programs and enforcement requirements
• Duties of certified G1 technicians vs G2/G3
2. Combustion Theory & Gas Properties
• Principles of complete vs incomplete combustion
• Air-to-fuel ratios and excess air calculations
• Properties of natural gas and propane (BTU values, density)
• Flame characteristics and combustion efficiency
• Carbon monoxide formation and hazards
3. Gas Piping Systems (Advanced)
• Pipe sizing for high BTU commercial systems
• Pressure drop calculations
• Materials: steel, copper, CSST
• Regulators, meters, and pressure controls
• Leak detection and testing procedures
4. Industrial & Commercial Appliances
• Boilers (fire-tube, water-tube)
• Make-up air units (MAUs)
• Rooftop units (RTUs)
• Process burners and ovens
• Infrared heaters and unit heaters
5. Controls & Electrical Systems
• Advanced control circuits (relay logic, PLC basics)
• Flame safeguard systems
• Safety interlocks and limit controls
• Wiring diagrams and troubleshooting
6. Venting & Air Supply
• Venting categories (I, II, III, IV)
• Draft, vent connectors, chimney systems
• Combustion air requirements (mechanical & natural)
• Negative pressure and backdrafting
7. Installation & Commissioning
• Equipment installation procedures
• Start-up and commissioning checks
• Gas pressure adjustments and manifold settings
• Combustion analysis (O₂, CO₂, CO readings)
8. Troubleshooting & Diagnostics
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• Systematic fault-finding methods
• Burner ignition failures
• Flame failure issues
• Control circuit faults
• Pressure and airflow problems
9. Safety & Hazard Management
• Carbon monoxide hazards
• Explosion risks and prevention
• Lockout/tagout procedures
• Confined space awareness
• Emergency response procedures
10. Maintenance & Inspection
• Preventive maintenance schedules
• Heat exchanger inspection
• Vent system inspection
• Efficiency testing and adjustments
1.A technician observes yellow-tipped flames in a commercial boiler burner during operation; what is
the most likely cause requiring correction?
A. Excess primary air
B. Insufficient combustion air
C. High gas pressure
D. Low gas pressure
Answer: B
Rationale: Yellow flames indicate incomplete combustion due to insufficient air supply.
2.
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During commissioning, manifold gas pressure is lower than specified by the manufacturer; what is the
correct first step?
A. Replace burner
B. Adjust regulator or supply pressure
C. Increase air supply
D. Shut down permanently
Answer: B
Rationale: Proper manifold pressure is essential for correct combustion.
3.
A rooftop unit repeatedly locks out on flame failure despite ignition spark presence; what is the most
likely issue?
A. High airflow
B. Faulty flame sensor
C. Excess gas pressure
D. Blocked vent
Answer: B
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4.
A combustion analyzer shows elevated CO levels during boiler operation; what should be done
immediately?
A. Increase gas input
B. Shut down and correct combustion
C. Ignore if stable
D. Add ventilation
Answer: B
5.
A gas piping system serving multiple appliances shows excessive pressure drop; what is the likely cause?
A. Oversized piping
B. Undersized piping
C. High gas quality
D. Low appliance demand
Answer: B
