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Heat & Glo • MEZZO36-C/ST-C, MEZZO48-C/ST-C, MEZZO60-C/ST-C, MEZZO72-C/ST-C Installation Manual • 2600-980 Rev. D • 9/19
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 and insulated in the same
manner as the thermal envelope of the home based on
the code requirements for that climate zone to prevent air
leakage and draft problems. The chase is an extension of
the building thermal envelope.
To further prevent drafts and air leakage, the wall shield
and ceiling firestops should be sealed with caulk or foil
tape with a minimum of 300 ºF continuous exposure
rating to seal gaps. Gas line holes and other openings
should be sealed with caulk or foil tape with a minimum
of 300 ºF continuous exposure rating or stuffed with unfaced
insulation. If the appliance is being installed on a cement sur
-
face, a layer of plywood may be placed underneath to pre
-
vent conducting cold up into the room.
Minimum height requirements for an exterior chase on a
top-vented appliance are shown in Figure 3.12. Reference
Figure 4.4 for additional clearances.
NOTICE:
Install appliance on hard metal or wood surfaces
extending full width and depth.
DO NOT
install directly on
carpeting, vinyl, 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.
Figure 3.12 Exterior Chase - Minimum Height Requirements
MEZZO36 = 70 IN.
MEZZO48 = 70 IN.
MEZZO60 = 70 IN.
MEZZO72 = 82 IN.
A
REQUIRED MINIMUM OFF TOP
MEZZO36 = 18 IN.
MEZZO48 = 18 IN.
MEZZO60 = 18 IN.
MEZZO72 = 30 IN.
3 IN. MIN.
* NOTE: If overhang “A” is less than 2
inches, clearance from top of termination
cap to bottom of overhang “B” MUST be a
minimum of 4 inches. If A is two inches
or greater, see Figure 4.4, “Minimum
Clearances for Termination.”
B*
C. Constructing the Appliance Chase
Note:
Figure 3.10 and Figure 3.11 show the fireplace installed
on the floor. However, this fireplace can be elevated off the
floor provided that the fireplace is properly supported by framing
materials and the ceiling clearances are maintained.
