08/04
31072 Rev G
19
MHC36 AND MHR36 INSTALLATION INSTRUCTIONS
Note:
Use only a noncombustible material to fin-
ish the face of the fireplace below the level of the
front standoffs. A noncombustible material such as
USG MICORE CV230 Mineral Fiber Board, or USG
DUROCK Cement Board is recommended for this
purpose.
Figure 18 - Air Clearance Around Gas Line
12. Complete the Enclosure
Complete the fireplace enclosure, allowing space for
outside air ducts and gas piping if desired. Electrical
wiring should not come in contact with the fireplace.
A
minimum clearance of 1 in. must be maintained
between the fireplace sides and the enclosure
(except at the nailing flange) as well as the fireplace
back and the enclosure.
See pages 9-11 for framing
details.
CAUTION:
When using a gas log set, the fireplace damper
must be set in the fully open position. This en-
sures proper venting of combustion products.
WARNING!
This fireplace was not tested by the fireplace manu-
facturer for use with an unvented gas log heater. To
reduce risk of injury, do not install an unvented gas
log heater in this fireplace unless it has been spe-
cifically tested and listed by Underwriter’s Labora-
tories Inc. for use in this specific model fireplace.
Unless the unvented gas log heater is tested and
listed for use in this factory built fireplace, a fire
hazard may be created that can result in a structure
fire.
13. Gas Log/Lighter Provisions
Knockouts are provided on both sides of the fireplace
to allow for connection of a certified gas log lighter or
a decorative gas appliance with a maximum input of
100,000 BTU/hour, incorporating an automatic gas
shutoff device and complying with the
Standard for
Decorative Gas Appliances for Installation in
Vented Fireplaces, ANSI Z21.60
. The decorative gas
appliance should be installed in accordance with the
National Fuel Gas Code, ANSI Z223.1-1980
. The side
refractories are designed to allow 1/2 in. iron pipe to
pass through. Use a noncombustible sealant to seal
any opening between the gas pipe and refractory on
the inside. Repack the insulation removed to seal
around the gas pipe where it exits the side of the
fireplace. A minimum 1-1/2 in. air clearance must be
provided around the 1/2 in. iron pipe for a minimum of
4 in. beyond the fireplace. See Figure 18.
This fireplace has been set up for installation of the
gas pipe on the right hand side. If it is necessary to
plumb the fireplace from the left hand side, remove
the gas cover plate and gas tube from the right hand
side of the fireplace and install on the left hand side.
Cover the hole in the right hand side outershell of the
fireplace with the cover plate that covered the gas tube.
CLEARANCES!
A minimum 1 in. air clearance must be maintained
at the back and sides of the fireplace assembly ex-
cept at the nailing flange where the clearance is
1/2 in.
Chimney sections at any level require a 2 in. mini-
mum air space clearance between the framing and
chimney section.
