An appliance with a positive vent pressure that avoids condensation operates under which category?

An appliance with a positive vent pressure that avoids condensation falls under Category 3. This category is designated for appliances that exhaust flue gases at a positive pressure and are specifically designed to operate with positive venting conditions. They typically utilize materials resistant to higher temperatures and do not allow for acidic condensate to accumulate, which makes them suitable for venting hot flue gases outdoors.

Category 3 appliances must ensure that venting systems are laid out to prevent condensation from forming in the pipes, thus allowing the appliance to function efficiently and safely without the risks associated with condensate. This capability distinguishes them from other categories, which might include negative pressure appliances or those that handle condensation differently.

Understanding the characteristics and operational requirements of Category 3 appliances is essential for ensuring the specific installation and maintenance protocols required for gas piping and venting systems.