G3 Safety and Compliance Standards 2 — Questions and Answers
Question 1: What is the maximum allowable ambient CO level in occupied spaces?
- 5 ppm
- 9 ppm
- 25 ppm (Correct answer)
- 50 ppm
Correct answer: 25 ppm
25 ppm is the action level above which investigation and corrective action are required.
Above 100 ppm, evacuation should be considered. Personal monitors typically alarm at 35 ppm.
Question 2: What safety device prevents gas flow if a standing pilot goes out?
- Pressure regulator
- Thermocouple and gas valve safety circuit (Correct answer)
- Barometric damper
- Electronic ignition module
Correct answer: Thermocouple and gas valve safety circuit
The thermocouple generates voltage from pilot heat; when the pilot goes out, voltage drops and the valve closes.
Typical thermocouple output is 25-35 millivolts. Shutoff takes 30-90 seconds after flame loss.
Question 3: What is the purpose of a high-temperature limit switch?
- To turn on the blower fan
- To shut off the burner if the appliance overheats (Correct answer)
- To regulate thermostat settings
- To control pilot light ignition
Correct answer: To shut off the burner if the appliance overheats
It shuts off the gas burner if temperatures exceed safe limits.
Common causes of tripping include dirty filters, blocked ducts, or failed blower motor.
Question 4: How often should gas appliances be professionally inspected?
- Only when something breaks
- At least annually, before each heating season (Correct answer)
- Every 5 years
- Monthly
Correct answer: At least annually, before each heating season
Annual inspection is the industry standard, ideally before heating season.
Annual maintenance includes leak checks, combustion analysis, heat exchanger inspection, and safety control testing.
Question 5: What is a TSSA red tag or compliance order?
- A quality rating for new equipment
- An official order requiring corrective action for a code violation, potentially shutting off gas (Correct answer)
- A warranty extension notice
- A building permit for gas work
Correct answer: An official order requiring corrective action for a code violation, potentially shutting off gas
A red tag documents a violation and requires correction, potentially with immediate gas shutoff.
Type A is immediately dangerous (gas shut off); Type B requires correction within a timeframe.
Question 6: What must happen when a gas meter or regulator is found damaged?
- Technician should repair it
- Gas utility must be contacted immediately as these are utility property (Correct answer)
- Homeowner should replace it
- Can be left in service if gas still flows
Correct answer: Gas utility must be contacted immediately as these are utility property
Meters and regulators are utility-owned. Report damage immediately.
Technicians are not authorized to repair, adjust, or bypass utility equipment.
G3 Safety and Compliance Standards 2
What is the maximum allowable ambient CO level in occupied spaces?