What is the name of the pipe that connects an appliance to a chimney or vent?

The term used for the pipe that connects an appliance, such as a furnace or boiler, to a chimney or vent is known as a vent connector. This type of pipe is specifically designed to carry combustion gases from the appliance to the vent system that ultimately exhausts these gases safely outside the building. Vent connectors are required to maintain appropriate clearances and installation practices to ensure safe operation and to prevent backdrafting, which could introduce dangerous gases back into the living space.

In contrast, exhaust pipes are generally more associated with the discharge of exhaust gases from the appliance itself rather than serving as a transitional piece to a chimney or vent. Chimney connectors, while similar in function to vent connectors, typically refer to a more specific design that may not encompass all the nuances of residential or commercial venting requirements. Flue pipes generally refer to the internal system within the chimney or venting system, which channels combustion gases up and out, but they do not specifically denote the connection from the appliance to the chimney or vent.