G3 Combustion and Venting Principles 2

Question 1

What is the primary purpose of a draft hood on a gas appliance?

Accepted Answer

To provide a safety break preventing excessive draft and backdraft

Answer

A draft hood prevents excessive updraft and protects against downdraft conditions.

Question 2

What is a Category I venting system?

Accepted Answer

Negative pressure with non-condensing flue gases

Answer

Category I operates under negative pressure with flue gas above the dew point.

Question 3

Why must vent connectors slope upward from appliance to chimney?

Accepted Answer

To ensure proper draft and prevent condensate pooling

Answer

Upward slope (minimum 1/4 inch per foot) maintains draft and prevents pooling.

Question 4

What happens when flue gases cool below the dew point in a non-condensing vent?

Accepted Answer

Condensation forms, potentially causing corrosion and failure

Answer

Acidic condensation corrodes vent material and can cause premature failure.

Question 5

What is the purpose of combustion air openings in a furnace room?

Accepted Answer

To supply oxygen for proper combustion and draft

Answer

Combustion air openings provide oxygen for combustion and draft operation.

G3 - Gas Technician Level 3 Certification Practice Test