QHT BIASI B3-B9 - Manual (Page 17)

Page 17
For boilers connected to gas vents or chimneys, vent installations shall be in
accordance with part 7, Venting of Equipment, of the National Fuel Gas Code, ANSI
Z223.1 or Section 7, Venting Systems and Air Supply for Appliances, of the CAN/
CGA B149, Installation Codes, or applicable provisions of the local building codes.
Vent connectors serving appliances vented by natural draft shall not be
connected into any portion of mechanical draft systems operating under positive
pressure.
7.3 Gas Venting