What is the primary function of a draft hood in a gas-fired appliance vent system?

What is the primary function of a draft hood in a gas-fired appliance vent system?

• A. To dilute combustion products with room air
• B. To admit fresh air to the burner
• C. To regulate gas flow to the burner
• D. To vent condensate from the chimney

Answer: (A)

The main function of a draft hood is to admit room air into the vented exhaust so the combustion products are diluted as they enter the vent. This dilution helps keep dangerous concentrations low and supports proper venting, reducing the chance of backdrafting when chimney conditions change. It is not meant to supply air to the burner, regulate gas flow, or vent condensate—that work is done by other components in the system.

The main function of a draft hood is to admit room air into the vented exhaust so the combustion products are diluted as they enter the vent. This dilution helps keep dangerous concentrations low and supports proper venting, reducing the chance of backdrafting when chimney conditions change. It is not meant to supply air to the burner, regulate gas flow, or vent condensate—that work is done by other components in the system.