11
Majestic • MARQ42STIN Installation Manual • 2272-980 Rev. H • 4/21
C. Constructing the Appliance Chase
A chase is a vertical box-like structure built to enclose the
gas appliance and/or its vent system. In cooler climates
the vent should be enclosed inside the chase.
NOTICE:
Treatment of ceiling firestops and wall shield
firestops and construction of the chase may vary with the
type of building. These instructions are not substitutes
for the requirements of local building codes. Therefore,
you MUST check local building codes to determine the
requirements to these steps.
NOTICE:
When installing a sprinkler head in a fireplace
chase, it is recommended to use a sprinkler head with a
sprinkler activation temperature classified as Extra High.
Keep sprinkler head away from vent and chimney.
Chases should be constructed in the manner of all out
-
side walls of the home to prevent cold air drafting prob
-
lems. The chase should not break the outside building
envelope in any manner.
Walls, ceiling, base plate and cantilever floor of the chase
should be insulated. Vapor and air infiltration barriers
should be installed in the chase as per regional codes for
the rest of the home. Additionally, in regions where cold
air infiltration may be an issue, the inside surfaces may be
NOTICE:
Install appliance on hard metal or wood surfaces
extending full width and depth.
DO NOT
install directly
on carpeting, vinyl, tile or any combustible material other
than wood.
WARNING! Risk of Fire!
Maintain specified air space
clearances to appliance and vent pipe:
• Insulation and other materials must be secured to prevent
accidental contact.
• The chase must be properly blocked to prevent blown
insulation or other combustibles from entering and
making contact with fireplace or chimney.
• Failure to maintain airspace may cause overheating and
a fire.
sheetrocked and taped (or an equivalent method may be
used) to achieve maximum air tightness.
To further prevent drafts, the wall shield and ceiling fire
-
stops should be caulked with caulk with a minimum of
300 ºF continuous exposure rating to seal gaps. Gas
line holes and other openings should be caulked with
caulk with a minimum of 300 ºF continuous exposure rating
or stuffed with unfaced insulation. If the appliance is being
installed on a cement surface, a layer of plywood may be
placed underneath to prevent conducting cold up into the
room.
Figure 3.4 Clearances to Combustibles
C
B
D
A
F
E=33 IN.
G
H
I
E=43 IN.
MINIMUM FRAMING DIMENSIONS*
A
B**
C*
D
E
F**
G**
H
I
Rough
Opening
(Vent Pipe)
Rough
Opening
(Height)
Rough
Opening
(Depth)
Rough
Opening
(Width)
Clearance
to ceiling
from opening
Clearance
to ceiling
from top of
appliance
Combustible
Floor
Combustible
Flooring
Sides of
Appliance
Front of
Appliance
Inches
10
46-1/2
30
60-1/4
43
33
0
See Note Below
1
36
Millime
-
ters
254
1181
762
1530
1092
838
0
See Note Below
25
914
* Adjust framing dimensions for interior sheathing (such as sheetrock)
** Fireplace may need to be elevated from the floor affecting framing height B, depending on hearth construction. See Section 3.D
for hearth and combustible floor requirements.
