Heatilator • Novus NNXT • 4055-879 • Rev E • 5/10
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B. Construct 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 enclosed inside the chase.
NOTICE: Treatment of ceiling fi restops and wall shield
fi restops 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.
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 fl oor of the chase
should be insulated. Vapor and air infi ltration barriers
should be installed in the chase as per regional codes for
the rest of the home. Additionally, in regions where cold
air infi ltration may be an issue, the inside surfaces may
be sheetrocked and taped for maximum air tightness.
To further prevent drafts, the wall shield and ceiling
fi restops should be caulked with high temperature caulk
to seal gaps. Gas line holes and other openings should
be caulked with high temperature caulk or stuffed with
unfaced insulation. If the appliance is being installed on
a cement slab, a layer of plywood may be placed under-
neath to prevent conducting cold up into the room.
