18 sample questions from the Ontario G3 exam question bank, with
the answers shown. These are a fair cross-section of all 9 topics —
not the easy ones. The full bank holds 1,184 questions.
What is the maximum BTU input rating for appliances that a G.2 certificate holder may install, inspect, alter, purge, activate, repair, service or remove?
100,000 Btuh
✓ 400,000 Btuh
200,000 Btuh
300,000 Btuh
Appliances & Heat Transfer
Which testing agency is NOT recognized for certifying propane appliances in the Province of Ontario?
Underwriters Laboratories of Canada
Underwriters Laboratories Incorporated International
Canadian Standards Association
✓ Transport Canada
Controls & Ignition
Controls & Ignition
What is a thermopile (powerpile) used for in gas appliances?
To measure gas pressure
To detect carbon monoxide
✓ To power both the combustion safety and control circuits
To regulate the gas flow rate
Controls & Ignition
'Yellow tipping' in a burner is an indication of:
✓ Too little primary air
Too much secondary air
Too little secondary air
Too much primary air
Electricity & Controls
Electricity & Controls
What setting must a gas technician use when measuring an unknown source of power with an analogue meter?
Lowest resistance setting
Highest resistance setting
Lowest voltage setting
✓ Highest voltage setting
Electricity & Controls
What is a capacitors job?
to increase load amps
none of the above
✓ to store energy
to decrease load amps and increase starting torque
Gas Code & Piping
Gas Code & Piping
After appliance installation, what is the minimum time the gas pressure must be maintained during the low-pressure leak test?
5 minutes
✓ 10 minutes
15 minutes
3 minutes
Gas Code & Piping
When purging a gas piping system, which appliance should be purged first?
The appliance with the largest pilot
The appliance closest to the meter
✓ The appliance farthest from the point of supply
The appliance with the highest input rating
Gas Properties & Combustion
Gas Properties & Combustion
What is the chemical formula for methane, the primary component of natural gas?
C4H10
C2H6
C3H8
✓ CH4
Gas Properties & Combustion
What is the boiling point of propane at atmospheric pressure?
-260degF (-162degC)
32degF (0degC)
✓ -44degF (-42degC)
212degF (100degC)
Regulations & TSSA
Regulations & TSSA
Meter and service regulator installations shall be made in accordance with:
CEC standard 3.6.7
✓ CSA standard Z662-99
TSSA standard 5.77.5
CSA standard Z240.4.1
Regulations & TSSA
A certificate holder must inform the Technical Standards and Safety Authority of a change of address within __________ days.
90
60
30
✓ 15
Safety & Workplace
Safety & Workplace
What type of piping are tube benders designed to be used for?
✓ Rolled copper tubing and thin-walled aluminum tubing
Steel and copper pipe
For bending aluminum pipe only
For bending water copper only
Safety & Workplace
What types of copper tubing are permitted by Code?
✓ any of the above
Type L
Type G
Type K
Tools & Measurements
Tools & Measurements
What are the three types of flue gas analyzers?
Tube type only
Liquid type only
Continuous sampling type only
✓ Tube, liquid, and continuous sampling
Tools & Measurements
What is the maximum pressure drop allowed for a propane piping system operating at 11 inches water column?
2.0 in w.c.
1.5 in w.c.
✓ 1.0 in w.c.
0.5 in w.c.
Venting & Combustion
Venting & Combustion
What is a vent connector?
✓ That part of venting system that conducts flue gases from flue collar of appliance to chimney or vent
The entire venting system
A connection fitting only
The termination of the vent
Venting & Combustion
In a forced-draft burner system, where is the combustion air supplied from?
✓ A fan or blower under sufficient pressure to overcome restrictions
Natural convection only
The barometric damper
The draft hood
Practising properly
Reading answers is not studying. Work a question before looking, get it wrong,
then find out why — that is what makes it stick. The app keeps every question you
answer incorrectly in a Challenge Bank so you can drill your weak spots rather
than the material you already know.