The furnace shall be located:
1. Where a minimum amount of air intake/vent piping and
elbows will be required.
2. As centralized with the air distribution as possible.
3. In an area where ventilation facilities provide for safe limits
of ambient temperature under normal operating condi-
tions. Ambient temperatures must not fall below 32
°
F (0
°
C).
4. Where it will not interfere with proper air circulation in the
confined space.
5. Where the outdoor combustion air/vent terminal will not be
blocked or restricted.
6. Where it will not interfere with the cleaning, servicing or
removal of other appliances.
CLEARANCES TO COMBUSTIBLES
Minimum clearances from combustible construction are shown
in inches in Table 3 above.
DUCTWORK
The duct system’s design and installation must:
1. Handle an air volume appropriate for the served space and
within the operating parameters of the furnace specifica-
tions.
2. Be installed in accordance with standards of NFPA (Na-
tional Fire Protection Association) as outlined in NFPA
pamphlets 90A and 90B (latest editions) or applicable
national, provincial, local fire and safety codes.
3. Create a closed duct system. The supply duct system must
be connected to the furnace outlet and the return duct
system must be connected to the furnace inlet. Both supply
and return duct systems must terminate outside the space
containing the furnace.
4. Generally complete a path for heated or cooled air to
circulate through the air conditioning and heating equip-
ment and to and from the conditioned space.
CAUTION: The cooling coil must be installed in the
supply air duct downstream of the furnace.
When the furnace is used in conjunction with a cooling coil,
the furnace must be installed parallel with, or on the upstream
side of the cooling unit to avoid condensation in the primary
heat exchanger.
When a parallel flow arrangement is used, the dampers or other
means used to control air flow must be adequate to prevent
chilled air from entering the furnace, and if manually operated,
must be equipped with means to prevent operating of either
unit unless the damper is in the full heat or cool position.
BELOW FREEZING LOCATIONS
It this furnace is installed in any area where the ambient
temperature may drop below 32° F, a UL listed self regulated
heat tape must be installed. It is recommended that self
regulating heat tape rated at 3 watts per foot be used. This must
be installed around the condensate drain lines in the uncondi-
tioned space. Always install the heat tape per the manufac-
turer’s instructions. Cover the self-regulating heat tape with
Fiberglas or other heat resistant, insulating material.
CAUTION: If this unit is installed in an unconditioned
space and an extended power failure occurs, there
will be potential damage to the condensate trap, drain
lines and internal unit components. Following a power
failure situation, Do Not Operate the Unit Until In-
spection and Repair Are Performed.
Supply Plenum Connection
Attach the supply plenum to the furnace
outlet duct connection flanges. This is
typically through the use of "S" cleat ma-
terial when a metal plenum is used. The
use of an approved flexible duct connec-
tor is recommended on all installations.
This connection should be sealed to pre-
vent air leakage.
If a matching cooling coil is used, it may
be placed directly on the furnace outlet
and sealed to prevent leakage. Follow the coil instructions for
installing the supply plenum.
On all installations without a coil, a removable access panel is
recommended in the outlet duct such that smoke or reflected
light would be observable inside the casing to indicate the
presence of leaks in the heat exchanger. This access cover
shall be attached in such a manner as to prevent leaks.
APPLICATION
TOP
FRONT
REAR
LEFT
SIDE
RIGHT
SIDE
FLUE
FLOOR/
BOTTOM
CLOSET
ALCOVE
ATTIC
LINE
CONTACT
UPFLOW MODELS
UPFLOW
1
3
0
0
0
0
COMBUSTIBLE
YES
YES
YES
NO
DOWNFLOW / HORIZONTAL MODELS
TOP
FRONT
REAR
LEFT
SIDE
RIGHT
SIDE
FLUE
FLOOR/
BOTTOM
CLOSET
ALCOVE
ATTIC
LINE
CONTACT
DOWNFLOW
1
3
0
0
0
0
1" (See Note 1)
YES
YES
YES
NO
TOP
FRONT
REAR
SUPPLY
AIR
RETURN
AIR
FLUE
FLOOR/
BOTTOM
CLOSET
ALCOVE
ATTIC
LINE
CONTACT
HORIZONTAL
0
3
0
1
1
0
COMBUSTIBLE
NO
YES
YES
YES(See Note 2)
NOTE 1: Special floor base or air conditioning coil required for use on combustible floor.
NOTE 2: Line contact only permitted between lines formed by the intersection of the rear panel and side panel (top in horizontal position) of the furnace jacket
and
building
joists,
studs
or
framing.
TABLE 3 - UNIT CLEARANCES
TO COMBUSTIBLES
UPFLOW MODELS APPLICATION
650.75-N4U
6
Unitary Products Group
