Fireplace And Hearth Dimensions; Placement In A Fireplace With Restrictive Barrier - Monessen Hearth NB18 Installation And Operating Instructions Manual

NB18/NB24 Gas Log Set
WARNING
This appliance is for installation only in a solid-fuel
burning masonry or UL127 factory-built fi replace,
vent free appliance, or in listed ventless fi rebox
enclosure. It has been design certifi ed for these
installations.
Exception: DO NOT install this appliance in a factory-
built fi replace 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 defi ned in their manual.
The NB and NBSC/SCR series unvented room heaters
are approved for installation into the following unvented
fi reboxes: MCUF 36/42, LCUF36, GCUF, GRUF 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 fi rebox"),
as long as fi rebox hearth dimensions meet the minimum
hearth dimensions shown below.
D
A
Model
NB18 w/18" Log
NB24 w/24" Log
NB24 w/30" Log
NB18SC,SCR w/18" Log
NB24SC/SCR w/24" Log
NB24SC/SCR w/30" Log
Figure 1 -
Minimum Hearth Dimensions
6
C
B
A B C D
26" 13" 18" 17"
29" 13" 22 ⁄ " 17"
1
4
33" 13" 25 ⁄ " 17"
1
4
28 ⁄ " 13" 20 ⁄ " 17"
1 1
2 4
31" 13" 25 ⁄ " 17"
1
4
35" 13" 25 ⁄ " 17"
1
4

FIREPLACE AND HEARTH DIMENSIONS

PLACEMENT IN FIREPLACE WITH A
RESTRICTIVE BARRIER
The following are guidelines for placing a gas log set in
a fi replace that has a restrictive barrier along the bottom
front opening of the fi replace. Some examples of barri-
ers are glass/screen door frames and sunken/recessed
fi replaces.
Height of Restriction
(x)
No Restriction
0" to 1 ⁄ "
1
2
Greater than 1 ⁄ " to 3"
1
2
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 fl oor of the fi replace 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 fi replace. Placement
of the receiver outside of the fi replace will extend the
battery life.
WARNING
Barriers such as the bottom of a glass door frame
placed in front of a gas log set can change the air
fl ow characteristics of the fi replace which in turn can
cause the unit to overheat and malfunction.
Height of restrictive barrier caused by glass
door frames, recessed fi replaces, etc. from
the base or bottom surface of the unit.
(Refer to table)
Glass door frames with adjustable louvers
should have the louvers fully open while
the unit is in operation
Figure 2 -
Reference Drawing of a Natural Flame Log Set in an Enclosure
Minimum Depth of
Fireplace/Firebox
13"
16"
16"
*
The log set should be placed against
or as near as possible to the rear
wall of the fi replace/fi rebox.
Depth of fi re-
place/fi rebox
(Refer to table)
81D0107