6
18NB/24NB Gas Log Set
81D0108
FIREPLACE AND HEARTH DIMENSIONS
W
ARNING
This appliance is for installation only in a
solid-fuel burning masonry or UL127 factory-
built fireplace, vent free appliance, or in
listed ventless firebox enclosure. It has been
design certified for these installations.
Exception:
DO NOT install this appliance
in a factory-built fireplace that includes
instructions stating it has not been tested
or should not be used with unvented gas
logs.
Use manufacturer's installation and clearance require-
ments as defined in their manual.
The NB and NBSC/SCR Series unvented room heaters
are approved for installation into the following unvented
fireplaces:
VF Series Fireboxes, Magnum36/42, Lo-Rider36 or
BUF
The NB and NBSC/SCR Series unvented room heaters
may also be installed into a Ventless Firebox Enclosure for
Gas Fired Decorative Type Unvented Room Heaters per
ANSI Z21.91 (typically referred to as a "Universal Firebox"),
as long as firebox hearth dimensions meet the minimum
hearth dimensions shown below.
A
C
D
B
Figure 1 -
Minimum Hearth Dimensions
IMPORTANT INFORMATION FOR THE
INSTALLATION OF THIS GAS LOG SET
PLACEMENT IN FIREPLACE WITH A
RESTRICTIVE BARRIER
The following are guidelines for placing a gas log set in
a fireplace that has a restrictive barrier along the bottom
front opening of the fireplace. Some examples of barri-
ers are glass/screen door frames and sunken/recessed
fireplaces.
Height of
Minimum Depth of
Restriction (x)
Fireplace/Firebox
No Restriction
13”
0” to 1
Z\x
”
16”
Greater than 1
Z\x
” to 3”
16”
Greater than 3”
*
*Any barrier greater than 3” placed in front of the gas log
set is not recommended by the manufacturer.
NOTE:
Non combustible material such as refractory brick
may be used to line the floor of the fireplace in order to raise
the height of the gas log set in relation to a restrictive barrier.
If the unit is raised, the minimum height dimension listed in
the homeowner’s manual must not be exceeded.
NOTE:
If the log set is equipped with a remote receiver, a
restrictive barrier may reduce the battery life by increasing
the ambient temperature inside the fireplace. Placement
of the receiver outside of the fireplace will extend the
battery life.
FP2252
set in enclosure
Glass door frames
with adjustable
louvers should have
the louvers fully
open while the unit
is in operation
Height of restrictive barrier
caused by glass door frames,
recessed fireplaces, etc. from
the base or bottom surface of
the unit. (Refer to Table)
Depth of Fire-
place/Firebox
Refer to Table
FP2252
Figure 2 -
Reference Drawing of a Natural Flame Log
Set in an Enclosure
Barriers such as the bottom of a glass door
frame placed in front of a gas log set can
change the air flow characteristics of the
fireplace which in turn can cause the unit to
overheat and malfunction.
W
ARNING
Model
A
B
C
D
18NB w/18” Log
26” 13”
18” 17”
24NB w/24” Log
29” 13” 22
Z\v
” 17”
24NB w/30” Log
33” 13” 25
Z\v
” 17”
18NBSC,SCR w/18” Log 28
Z\x
” 13” 20
Z\v
” 17”
24NBSC/SCR w/24” Log
31” 13” 25
Z\v
” 17”
24NBSC/SCR w/30” Log
35” 13” 25
Z\v
” 17”
The log set should be
placed against or as
near as possible to the
rear wall of the fireplace/
firebox.
