Which type of appliance uses a small fan to assist in draft?

Induced draft appliances are designed specifically to utilize a fan that actively assists in creating the necessary draft for proper combustion. This is crucial for venting exhaust gases out of the appliance and ensuring that fresh air is drawn in for the combustion process. The inclusion of a fan helps to counteract any negative pressure in the flue or surrounding environment, thereby enhancing efficiency and safety by ensuring that combustion gases are effectively vented outside.

Sealed combustion appliances, in contrast, rely on two separate air passages, one for intake and one for exhaust, thus not requiring a fan to assist in draft. Open combustion appliances take air from the surrounding environment for combustion and do not typically use a fan for draft assistance. Class C appliances refer to a category associated with the type of venting system used and do not inherently imply the use of a fan for draft support.