Draft Inducer Application Boilers Furnaces Water Heaters For Fuel Type Coal Natural Gas Oil For Appliance Type Oil or Gas-Fired Furnaces Water Heaters Boilers Maximum Vent Pipe Diameter 8 in Minimum Vent Pipe Diameter 5 in For Pipe Slot Height 5 1/8 in For Pipe Slot Width 8 1/2 in Maximum Heater BTU Input for Gas Appliance 353 000 BtuH Maximum Heater BTU Input for Oil Appliance 412 000 BtuH Inlet Diameter 8 in Outlet Diameter 12 in For Vent Pipe Diameter 8 in