GCSS96 Installation Manual
7
• If the furnace is used in connection with a cooling coil
unit, install the furnace upstream or in parallel with the
cooling coil unit. Premature heat exchanger failure will
result if the cooling unit is placed ahead of the furnace.
For vertical (upflow or downflow) applications, the
minimum cooling coil width shall not be less than
furnace width minus 1”. Additionally, a coil installed
above an upflow furnace or under a counterflow
furnace may be the same width as the furnace or
may be one size larger than the furnace. Example:
a “C” width coil may be installed with a “B” width
furnace.
For upflow applications, the front of the coil and
furnace must face the same direction.
• If the furnace is installed in a residential garage,
position the furnace so that the burners and ignition
source are located not less than 18 inches (457 mm)
above the floor. Protect the furnace from physical
damage by vehicles.
• If the furnace is installed horizontally, ensure the access
doors are not on the “up/top” or “down/bottom” side
of the furnace.
• Do not connect this furnace to a chimney flue that
serves a separate appliance designed to burn solid
fuel.
• On Counterflow Installations, the air conditioning
coil must be downstream on the supply (positive)
side of the furnace heat exchanger.
• Counterflow Installation over a noncombustible
floor. Before setting the furnace over the plenum
opening, ensure the surface around the opening is
smooth and level. A tight seal should be made
between the furnace base and floor by using a
silicone rubber caulking compound or cement grout.
• Counterflow Installation over a combustible floor. If
installation over a combustible floor becomes necessary,
use an accessory subbase (see Specification Sheet
applicable for your model for details.) A special accessory
subbase must be used for upright counterflow unit
installations over any combustible material including
wood. Refer to subbase instructions for installation
details. Follow the instructions with the subbase for
proper installation. Do not install the furnace directly
on carpeting, tile, or other combustible material other
than wood flooring. (NOTE: The subbase will not be
required if an air conditioning coil is installed between
the supply air opening on the furnace and the floor.)
POSITION* SIDES REAR FRONT BOTTOM FLUE TOP
Upflow 0" 0" 3" C 0" 1"
Horizontal 6" 0" 3" C 0" 6"
C = If placed on combustible floor, floor MUST be wood only.
*M SS[92 & 96]* M INIM UM CLEARANCES TO COMBUSTIBLE MATERIALS
(INCHES)
POSITION* SIDES REAR FRONT BOTTOM FLUE TOP
Counterflow0"0"3"NC0"1"
Horizontal 6" 0" 3" C 0" 6"
C = If placed on combustible floor, floor MUST be wood only.
NC = For installation on non-combustible floors only. A combustible subbase
must
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*CSS[92 & 96]* MINIMUM CLEARANCES TO COMBUSTIBLE MATERIALS
(INCHES)
TOP
BOTTOM
SIDE SIDE SIDE
TOP
BOTTOM
Upflow Counterflow Horizontal
Figure 1
CLEARANCES AND ACCESSIBILITY
NOTES:
• For servicing or cleaning, a 24” front clearance is
required.
• Unit connections (electrical, flue and drain) may
necessitate greater clearances than the minimum
clearances listed above.
• In all cases, accessibility clearance must take
precedence over clearances from the enclosure
where accessibility clearances are greater.
Installations must adhere to the clearances to combustible
materials to which this furnace has been design certified.
The minimum clearance information for this furnace is pro-
vided on the unit’s clearance label. These clearances must
be permanently maintained. Clearances must also accom-
modate an installation’s gas, electrical, and drain trap and
drain line connections. If the alternate combustion air in-
take or vent/flue connections are used additional clearance
must be provided to accommodate these connections. Refer
to Vent/Flue Pipe and Combustion Air Pipe for details.
NOTE: In addition to the required clearances to combustible
materials, a minimum of 24 inches service clearance must be
available in front of the unit.
A furnace installed in a confined space (i.e., a closet or utility
room) must have two ventilation openings with a total minimum
free area of 0.25 square inches per 1,000 BTU/hr of furnace
input rating. Refer to Specification Sheet applicable to your model