Using tables from the National Fuel Gas Code or our Sizing & Application Guide, determine the diameter of venting required. The Sizing & Application Guide also offers tips on good design including multi-appliance system sizing and design. The System Design and Installation Guide is an additional resource.
The tee collar may be used to cover the rough wall opening and the exposed double-wall branch of the tee. The 3-40TVC collar features a knock-out for a 3" or 4" single-wall connector. For double-wall connections, see the vent collar.