What device regulates draft and prevents excessive draft in a fuel burning appliance?

The barometric damper is designed specifically to help regulate draft within a chimney system connected to fuel-burning appliances. Its primary function is to automatically adjust to changes in draft pressure, ensuring that it neither becomes too strong nor too weak. By maintaining a balanced draft, the barometric damper helps prevent issues like downdrafts, which can cause poor combustion and potential safety hazards, as well as excessive draft, which can lead to increased fuel consumption and inefficient operation.

In contrast, other devices listed have different functions. A draft inducer is used to enhance draft by mechanically pulling combustion gases from the appliance, which is beneficial in situations where natural draft is insufficient. A combustion air vent provides fresh air to support combustion, but it does not regulate the draft itself. An exhaust fan removes combustion products from the appliance but can also create negative pressure in the system, which makes managing draft more complex. Thus, the functionality of the barometric damper makes it the right choice for regulating draft and preventing excessive draft in fuel-burning appliances.