Lennox DT3025 Installation Instructions Manual page 18

HORIZONTAL VENTING WITHOUT ELBOWS
(DR/DRH - Rear Vent Units)
ONLY THE RECTANGULAR TERMINATION MAY BE USED.
RIGID VENT PIPE SHOWN; FLEXIBLE VENT PIPE
MAY ALSO BE USED.
**For 3025, 3530, and 4035 models
H = 28 in. (711 mm) Maximum.
**For 4540 models
H = 18 in. (457 mm) Maximum.
**H
7 in.
FIGURE 26
Rectangular termination shown;
round termination may also be used.
V
H1 H1 + H2 + H3
1 ft. min. 2 ft. max.
2 ft. min. 4 ft. max.
3 ft. min. 6 ft. max.
4 ft. min. 8 ft. max.
5 ft. min. 8 ft. max.
6 ft. min. 8 ft. max.
20 ft. max. 8 ft. max.
*NOTE: THE LONGEST LENGTH OF FLEX AVAILABLE
IS 48 INCHES OF COMPRESSED FLEX.
DR/DRH HORIZONTAL VENTING FIGURES
Firestop/Spacer must be used any
time vent pipe passes through
combustible floor or ceiling or wall.
HORIZONTAL VENTING USING THREE 90 _ ELBOWS
(DR/DRH - Rear Vent Units)
RIGID VENT PIPE SHOWN; *FLEXIBLE VENT
3 ft. max.
H3
6 ft. max.
9 ft. max.
12 ft. max.
15 ft. max.
Firestop/Spacer must be used any
17 ft. max.
time vent pipe passes through
17 ft. max.
combustible floor or ceiling or wall.
HORIZONTAL VENTING USING TWO 90 _ ELBOWS
*NOTE: THE LONGEST LENGTH OF FLEX AVAILABLE
IS 48 INCHES OF COMPRESSED FLEX.
PIPE MAY ALSO BE USED.
H2
FIGURE 28
P a g e 1 8
(DR/DRH - Rear Vent Units)
RIGID VENT PIPE SHOWN; *FLEXIBLE VENT
PIPE MAY ALSO BE USED.
H1
H2
Firestop/Spacer must be used any
combustible floor or ceiling or wall.
V
Rectangular termination shown;
round termination may also be used.
V H1
1 ft. min. 2 ft. max. 3 ft. max.
2 ft. min. 4 ft. max.
3 ft. min. 6 ft. max.
4 ft. min. 8 ft. max.
5 ft. min. 8 ft. max.
6 ft. min. 8 ft. max.
20 ft. max. 8 ft. max. 17 ft. max.
FIGURE 27
V
H1
time vent pipe passes through
H1 + H2
6 ft. max.
9 ft. max.
12 ft. max.
15 ft. max.
17 ft. max.