A vent cap is installed at the top of your venting and used to streamline the exhaust as it is dispensed from your heater. They also keep the weather and debris out of your intake venting. They can either extend from the side wall in a horizontal venting application or through the roof in a vertical application. For all Williams Direct Vent furnaces.
Replacement parts lists and exploded view diagrams are available for Williams Furnaces under the "Manuals and Guides" tab. Please refer to the appropriate section for your specific furnace.