Lennox Hearth L20 BF-2 - Manual (Page 7)

INSTALLATION - MODEL L20 DVF-2 (DIRECT-VENT) VENTING REQUIREMENTS.
This appliance is designed to be vented with a 4” x 6 5/8” direct-vent pipe. Each direct-vent appliance must use its own separate
vent system.
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VERTICAL TERMINATION WITH
NO OFFSETS
Min. Vertical Pipe Length: 5 feet
Max. Vertical Pipe Length: 25 feet
VERTICAL TERMINATION
WITH 2 OFFSETS
Min. Vertical Pipe From Appliance to first offset:
2 feet.
Min. Total Vertical Pipe Length: 5 feet
Max. Total Vertical Pipe Length: 25 feet
HORIZONTAL TERMINATION
WITH 1 OFFSET
Min. Vertical Pipe From Appliance to offset: 2
feet.
Max. Vertical Pipe Length: 25 feet
Maximum total offsets allowed: Not to exceed 180 degrees.
Maximum allowable horizontal pipe run is 12 feet.
With 2 feet of vertical pipe installed from the appliance (* see note), a 2 foot maximum horizontal run allowed. For installations with
more than 2 feet of vertical pipe, calculate allowable horizontal run as indicated in applicable illustration above.
See page 10 for Vent Termination Requirements.
Also see pipe manufacturers instructions for additional vent installation requirements.
Horizontal vent clearances: 3“ minimum top 1“ minimum on bottom and sidewalls.
Vertical vent clearances: 1” minimum.
Install vent support brackets every 4 feet of vertical pipe unless otherwise specified by vent manufacturer.
* Note: If using Propane Gas (LP), it may be necessary to install (as a minimum) 3 feet of vertical pipe from the appliance prior to an
offset to ensure optimum product performance. This may be necessary due to variations in vent configuration and other numerous fac-
tors which affect exhaust flow and air delivery such as BTU value, ambient temperature, wind conditions, altitude, etc.
5 Feet
Min.
25 Feet
Max.
5 Feet
Min.
25 Feet
Max.
25
Feet
Max.
12 Feet Max.
For every 1 feet of vertical
pipe (from unit to first offset),
2 feet of horizontal run is
allowed (not to exceed 12 ft.
Example – with a 6’ ver-
tical pipe off unit, 12’ of
horizontal run is allowed.
At 2’ Min. Vertical, 2’ Max.
Horizontal is allowed.
* 2 Feet Min.
Wall
Penetration
Detail
At 2’ Min. Vertical, 2’ Max.
Horizontal is allowed.
Horizontal
runs require
¼” rise per
foot.
* 2 Feet Min.
For every 1 feet of
vertical pipe (from
unit to first offset), 2
feet of horizontal
run is allowed (not
to exceed 12 ft.
Example – with a 6’ ver-
tical pipe off unit, 12’ of
horizontal run is allowed.