TSSA G3 Gas Technician Practice Test
Free · 200 Questions.

• Reactivating an appliance that was installed earlier
• Cleaning and lubricating an appliance already in service
• Replacing a vent connector on an existing appliance
• The initial activation of a newly converted appliance

Why: Section 22(2) bars a G3 from the initial activation of a new or newly converted appliance. Reactivating a previously installed appliance, cleaning and lubricating it, and replacing a vent connector are all listed in s. 22(1).

• 5 ft (1.5 m)
• 25 ft (7.5 m)
• 10 ft (3 m)
• 20 ft (6 m)

Why: Clause 6.23.4 c) i) requires the discharge point to be at least 10 ft (3 m) from a source of ignition, with maximum precautions taken to remove or shut off any ignition source before purging begins. The 25 ft (7.5 m) figure belongs to mechanical air intakes.

• Positive vent static pressure with a flue loss under 17%
• Positive vent static pressure with a flue loss of 17% or more
• Nonpositive vent static pressure with a flue loss of 17% or more
• Nonpositive vent static pressure with a flue loss under 17%

Why: Category I appliances operate with nonpositive vent static pressure and a flue loss of at least 17% (efficiency about 83% or less), such as a standard natural-draft furnace. Category II keeps nonpositive pressure but has lower flue loss; III and IV run at positive pressure.

• About 15 mV; replace it below 10 mV
• About 30 mV; replace it below 20 mV
• About 30 mV; replace it below 10 mV
• About 250 mV; replace it below 200 mV

Why: An unloaded thermocouple should read about 30 mV and is replaced if it produces under 20 mV. About 15 mV is the expected closed-circuit (under load) reading, where under 10 mV means replacement.

• 10 ppm (11.5 mg/m3)
• 25 ppm (28.6 mg/m3)
• 35 ppm (40.1 mg/m3)
• 50 ppm (57.3 mg/m3)

Why: The 24-hour limit is 10 ppm, set to protect people with coronary artery disease from heart-related effects. The 25 ppm value is the shorter 1-hour limit, and higher values are closer to workplace exposure limits.