Gas Log Set Installation

6
NBST27 Unvented Gas Log Set
Monessen • NBST27 Gas Log Set Installation/Owner's Manual • 81D3032 • Rev A • 08/16
FIREPLACE AND HEARTH DIMENSIONS
Use the replace manufacturer's installation and clear-
ance requirements as dened in their manual.
The NBST27 unvented room heater is approved for installa-
tionintothefollowingunventedreboxes:LSTF36,LPF36,
LRF36, LLF36
The NBST27 unvented room heater may also be installed
into a Ventless Firebox Enclosure for Gas Fired Decorative
Type Unvented Room Heaters per IAS Requirement No.
2-97 ANSI Z21.91-2001 (typically referred to as a "Univer-
salFirebox"),aslongasreboxhearthdimensionsmeet
the minimum hearth dimensions shown below.
32”
21¹⁄₂”
21¹⁄₂”
FP2361
fireplace dims
Figure 1 -
Hearth Minimum Dimensions for Solid Fuel Burning Fire-
places and UL127 Factory Built Fireplaces
FP2362
fireplace barrier
X
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replaces,etc.fromthe
base or bottom surface of the unit.
(Refer to Table)
Refer to
Table
Figure 2 -
Reference Drawing of NBST27 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
ow characteristics of the replace which in turn can
cause the unit to overheat and malfunction.
WARNING
This appliance is for installation only in a solid-fuel
burning masonry or UL127 factory-built replace,
vent free appliance, or in listed ventless rebox
enclosure. It has been design certied for these
installations.
Exception: DO NOT install this appliance in a factory-
built replace that includes instructions stating
it has not been tested or should not be used with
unvented gas logs.
WARNING
PLACEMENT IN FIREPLACE WITH A
RESTRICTIVE BARRIER
The following are guidelines for placing a gas log set in a
replacethathasarestrictivebarrieralongthebottomfront
openingofthereplace.Someexamplesofbarriersare
glass/screendoorframesandsunken/recessedreplaces.
Height of Restriction
(x)
Minimum Depth of
Fireplace/Firebox
No Restriction 21
1
⁄2”"
0" to 1
1
⁄2" 25
1
⁄4"
Greater than 1
1
⁄2" to 3" 27
1
⁄4"
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oorofthe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replace.Placement
of the receiver outside of the replace will extend the
battery life.