Ontario Gas Technician 1 (G1) Certification
Exam With Actual Questions & Verified
Answers, Plus Explained Rationales/Expert
Verified For Guaranteed 100% Pass
2026/Latest Update/Instant Download Pdf
1. What is the primary purpose of a flame safeguard system in gas-
fired equipment?
A. Increase fuel efficiency
B. Reduce emissions
C. Shut off fuel supply if flame is not proven
D. Regulate gas pressure
Rationale: Flame safeguard systems ensure safety by
immediately shutting off the fuel supply if a flame is not
detected, preventing unburned gas accumulation and potential
explosion.
2. Which instrument is commonly used to measure gas pressure in
inches of water column?
A. Thermocouple
B. Manometer
C. Hygrometer
D. Barometer
Rationale: A manometer is specifically designed to measure low
gas pressures, typically expressed in inches of water column for
gas systems.
3. What is the minimum acceptable oxygen level in flue gases for
efficient combustion?
A. 0%
, B. 2%
C. 3–6%
D. 10%
Rationale: An oxygen level of 3–6% indicates proper combustion
with sufficient excess air while maintaining efficiency.
4. Which component regulates downstream gas pressure in a gas
train?
A. Gas valve
B. Pressure regulator
C. Orifice plate
D. Thermostat
Rationale: Pressure regulators maintain a constant downstream
pressure regardless of fluctuations in supply pressure.
5. What is the purpose of a draft hood?
A. Increase combustion temperature
B. Stabilize draft and prevent backdrafting
C. Reduce fuel consumption
D. Filter flue gases
Rationale: Draft hoods stabilize chimney draft and prevent
downdrafts from affecting burner operation.
6. What is the ignition temperature of natural gas approximately?
A. 100°C
B. 300°C
C. 540°C
D. 900°C
Rationale: Natural gas ignites at approximately 540°C, making
proper ignition systems essential for safe operation.
7. Which code governs gas installations in Ontario?
A. CSA B52
, B. CSA B149
C. NFPA 54
D. ASME Section IV
Rationale: CSA B149 is the governing code for gas installation
and handling in Ontario.
8. What device proves airflow before ignition in forced draft
systems?
A. Limit switch
B. Thermostat
C. Air proving switch
D. Gas valve
Rationale: Air proving switches confirm adequate airflow before
allowing ignition to proceed.
9. What is the main function of a thermocouple?
A. Measure pressure
B. Generate voltage from heat to prove flame
C. Control airflow
D. Regulate gas flow
Rationale: Thermocouples generate a small voltage when
heated, used to confirm pilot flame presence.
10. Which gas has a higher heating value?
A. Propane
B. Natural gas
C. Hydrogen
D. Butane
Rationale: Natural gas has a higher heating value when
measured per unit volume compared to propane.
11. What is the purpose of a vent damper?
A. Increase gas flow
Exam With Actual Questions & Verified
Answers, Plus Explained Rationales/Expert
Verified For Guaranteed 100% Pass
2026/Latest Update/Instant Download Pdf
1. What is the primary purpose of a flame safeguard system in gas-
fired equipment?
A. Increase fuel efficiency
B. Reduce emissions
C. Shut off fuel supply if flame is not proven
D. Regulate gas pressure
Rationale: Flame safeguard systems ensure safety by
immediately shutting off the fuel supply if a flame is not
detected, preventing unburned gas accumulation and potential
explosion.
2. Which instrument is commonly used to measure gas pressure in
inches of water column?
A. Thermocouple
B. Manometer
C. Hygrometer
D. Barometer
Rationale: A manometer is specifically designed to measure low
gas pressures, typically expressed in inches of water column for
gas systems.
3. What is the minimum acceptable oxygen level in flue gases for
efficient combustion?
A. 0%
, B. 2%
C. 3–6%
D. 10%
Rationale: An oxygen level of 3–6% indicates proper combustion
with sufficient excess air while maintaining efficiency.
4. Which component regulates downstream gas pressure in a gas
train?
A. Gas valve
B. Pressure regulator
C. Orifice plate
D. Thermostat
Rationale: Pressure regulators maintain a constant downstream
pressure regardless of fluctuations in supply pressure.
5. What is the purpose of a draft hood?
A. Increase combustion temperature
B. Stabilize draft and prevent backdrafting
C. Reduce fuel consumption
D. Filter flue gases
Rationale: Draft hoods stabilize chimney draft and prevent
downdrafts from affecting burner operation.
6. What is the ignition temperature of natural gas approximately?
A. 100°C
B. 300°C
C. 540°C
D. 900°C
Rationale: Natural gas ignites at approximately 540°C, making
proper ignition systems essential for safe operation.
7. Which code governs gas installations in Ontario?
A. CSA B52
, B. CSA B149
C. NFPA 54
D. ASME Section IV
Rationale: CSA B149 is the governing code for gas installation
and handling in Ontario.
8. What device proves airflow before ignition in forced draft
systems?
A. Limit switch
B. Thermostat
C. Air proving switch
D. Gas valve
Rationale: Air proving switches confirm adequate airflow before
allowing ignition to proceed.
9. What is the main function of a thermocouple?
A. Measure pressure
B. Generate voltage from heat to prove flame
C. Control airflow
D. Regulate gas flow
Rationale: Thermocouples generate a small voltage when
heated, used to confirm pilot flame presence.
10. Which gas has a higher heating value?
A. Propane
B. Natural gas
C. Hydrogen
D. Butane
Rationale: Natural gas has a higher heating value when
measured per unit volume compared to propane.
11. What is the purpose of a vent damper?
A. Increase gas flow
