The Reznor RZ220780 Venter Assembly is a replacement combustion exhaust component designed for compatible Reznor gas-fired unit heaters. It operates with the heater’s combustion system to create the draft needed to move combustion gases safely through the venting system. Proper venter operation supports efficient combustion and helps maintain safe exhaust flow from the heat exchanger.... https://www.partshnc.com/reznor-rz220780-venter-assembly-115v-100-125