53
Avoid short horizontal offsets with 90
deg. Elbows. Short offsets can be
difficult to slope and may trap con-
densate.
Use 45 deg. Elbows where
possible, to ensure conden-
sate drainage.
Slope vent pipe back to the
furnace at least ¼” per foot
A14546
Fig. 42 -- Near Furnace Vent Connections
FURNACE
PIPE DIAMETER
TRANSITION IN
VERTICAL SECTION
NOT IN
HORIZONTAL
SECTION
A93034
Fig. 43 -- Combustion Air and Vent Pipe Diameter Transition Location and Elbow Configuration
59SP2A