Lennox ELITE EL196UHE Installation Instructions Manual page 18

Use the following steps to correctly size vent pipe diam-
eter.
Piping Size Process
What is the
1
furnace capacity?
Which style termination
2
being used?
Standard or
concentric?.
Which needs
most elbows?
3
Intake or
exhaust?
How many elbows?
4
Count all elbows inside
and outside house.
5
Desired pipe size?
What is the altitude of
6
the furnace installation?
Find max intake or
exhaust pipe length.
7
Includes all vent pipe and
elbows inside and outside
the house.
Figure 24
Do not use screens or perforated metal in exhaust or
intake terminations. Doing so will cause freeze-ups and
may block the terminations.
MINIMUM VENT PIPE LENGTHS
EL196UHE Model
030, 045, -070, -090, 110
*Any approved termination may be added to the minimum
length listed. Two 45 degree elbows are the equivalent of one
90 degree elbow.
Page 18
IMPORTANT
TABLE 4
MIN. VENT LENGTH*
15 ft. or 5 ft. plus 2 elbows
or 10 ft. plus 1 elbow