The Bosch Vertical Vent Kit (H/P VVT) is a 5" Galvanized, Type B Vertical Vent Kit. This vertical vent kit includes a 5" x 12" pipe, (2) 5" flexible 90 degree elbows, a 5" fire stop support, a 5" roof flashing, a 5" storm collar, and a 5" rain cap. The HP VVT Vertical Vent Kit is manufactured by Selkirk and is used only for the Bosch Therm 520HN and 520PN naturally drafting heaters. The H/P VVT vent kit will also work for the older retail models 1600H and 1600P.
The venting system must be designed and constructed so as to develop a positive flow adequate to remove flue gases to the outdoors. Consult the National Fuel Gas Code if the vent will have elbows or share venting with another natural draft appliance. The vent system must have at least a 12" rise off the top of the heater before any elbows or vent connectors.