including the starting 45 elbow at the flue collar when using rigid venting.) Note: Must use optional rigid pipe adapter (Part# 510-994) when using Rigid Pipe Venting Systems. Horizontal (Feet) 0 2 4 6 0 10 12 I I I ! I I Is 16 • 14I a.0 12 E 10 0 u_ a—0 .0 6 stu 2— > 0 • VENT RESTRICTOR SETTIN