What are the types of drafts used in HVAC systems?

The correct choice identifies the types of drafts used in HVAC systems as induced draft, natural draft, and forced draft.

Induced draft refers to the method where a fan or blower is used to create a low-pressure area, helping to draw air or flue gases out of the system, enhancing the efficiency of exhaust. This is commonly found in applications like boilers and furnaces where it is crucial to remove combustion products effectively.

Natural draft relies on the buoyancy of warm air, which naturally rises. It is primarily driven by temperature differences between the hot gases inside a flue and the cooler external air, making it a passive and energy-efficient method of ventilation. This type of draft is often seen in traditional chimney systems.

Forced draft involves the use of a blower or fan to push air into the combustion process, creating a positive pressure environment. This method allows for better control over airflow and can increase the efficiency of combustion, making it a popular choice in modern heating and cooling systems.

The other options contain terms that do not accurately represent the standard terminology for drafts in HVAC applications, either by mixing unrelated types of drafts or using terminology not typically used in the field. Understanding these distinctions is critical for those working with HVAC systems, as it directly impacts efficiency and