General Installation Information; Fireplace And Hearth Dimensions; Placement In A Fireplace With A Restrictive Bar- Rier - Vermont Castings NBST27 Installation Instructions Manual

NBST27 Unvented Gas Log Set
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 the fireplace manufacturer's installation and clear-
ance requirements as defined in their manual.
The NBST27 unvented room heater is approved for instal-
lation into the following unvented fireplaces:
VF Series Fireboxes: GPF36, GSTF36, GRCF36,
GLCF36, 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 "Universal
Firebox"), as long as firebox hearth dimensions meet the
minimum hearth dimensions shown below.
21 "
32"
Figure 1 -
Hearth Minimum Dimensions for Solid
Fuel Burning Fireplaces and UL127
Factory Built Fireplaces
FP2361
Barriers such as the bottom of a glass door
fireplace dims
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.
6
IMPORTANT INFORMATION FOR THE
INSTALLATION OF THIS GAS LOG SET
PLACEMENT IN A 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.
Restriction (x)
No Restriction
1/2" to 1Z\x"
Greater than 1Z\x" to 3"
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.
FP2361
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
21 "
battery life.
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)
Figure 2 -
Reference Drawing of NBST27 Log Set in an Enclosure

FIREPLACE and HEARTH DIMENSIONS

Height of Minimum Depth of
Fireplace/Firebox
X
FP2362
21Z\x"
25Z\v"
27Z\v"
*
FP2362
Refer to
Table
81D3032