Warm air furnace – Fedders F80A User Manual

Page 5

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WARM AIR FURNACE

UPFLOW INSTALLATION

This furnace comes assembled for installation in the upflow
position and ready for vertical venting. In the event that the
furnace will be installed in another position, the following
guidelines should be followed.

COUNTERFLOW INSTALLATION

SUGGESTED METHOD FOR
SUSPENDING HORIZONTAL FURNACE

ALLOW ENOUGH ANGLE
IRON OVERHANG TO
PERMIT OPENING THE
BLOWER DOOR

3/8 INCH THREADED ROD

2 INCH ANGLE IRON

JAM NUTS

LOCK WASHER

FLAT WASHER

SUPPLY AIR PLENUM

RETURN AIR PLENUM

FIGURE 1: SUSPENDED INSTALLATION

• If the furnace is to be located in an area where the

combustion air is laden with chemical compounds such
as bromine, chlorine or fluorine, as may be found in
swimming pool chemicals, laundry detergents, etc., use
outdoor air for combustion. These compounds when
exposed to flame, form acids, which attack the heat
exchanger and other components.

A partial list of these contaminants includes:

- Aerosols, particularly CFC based aerosols
- Air fresheners
- “Airplane” glue and similar cements
- Ammonia, as is commonly found in permanent wave

solutions used in women’s hair dressing salons

- Anti-static fabric softeners used in clothes dryers
- Carbon tetrachloride
- Chlorinated cleaners and waxes
- Chlorine and bromine based swimming pool chemicals

and treatments

- Deicing salts or chemicals, rock salt, etc.
- Dry cleaning solutions such as perchloroethylene
- Halogen based refrigerants including R-12 and R-22
- Hydrochloric acid, muriatic acid, or other acid based

masonry washing compounds

- Polyurethane and similar derivatives fumes
- Printer’s inks, paint removers, furniture strippers,

varnishes, varsol, toluene, etc.

- Water softener salts and chemicals

INSTALLATION POSITIONS

NONSUSPENDED INSTALLATION

Maintain clearances to combustibles as outlined in Table 2
on page 5. The furnace must be supported in such a way as
to not allow twisting or sagging of the cabinet.

SUSPENDED INSTALLATION

Refer to Figure 1 (below). Maintain clearances to
combustibles as outlined in Table 2 on page 5. The furnace
may be suspended by field fabricating a cradle of angle iron
and threaded rod. Secure the furnace with 2 inch minimum
slotted angle or equivalent, as shown in Figure 1 (below).
The furnace must be supported in such a way as not to
allow twisting or sagging of the cabinet. Position the
supports so as not to interfere with accessing the burner
and blower compartments.

The opening in the floor must provide adequate clearances
to the combustible material.

According to the Clearances to Combustibles Table 2 on
page 5, 1/2 inches clearance will be required between the
plenum and the combustible material. If installed on a
non-combustible material, zero clearance is required.

Inducer position changes required shall be performed in
accordance with the inducer rotation instructions in the
Furnace Venting section on page 8 of this manual. In the
counterflow installation, this furnace can only vent through
the left or right side of the furnace.

HORIZONTAL INSTALLATION

Inducer position changes required shall be performed in
accordance with the inducer rotation instructions in the
Furnace Venting section on page 8 of this manual. In the
horizontal installation, it is not permissible to vent
downwards. Therefore the orientation of left or right
horizontal position will determine the inducer orientation.

NOTE: It is not permissable to use a rear return on this
furnace although side and end returns may be used.

AIR CONDITIONING

This furnace may be used as part of an air conditioning
system. The furnace wiring and control system are “air
conditioning ready”. There are the following factors to
consider:

The air conditioning evaporator coil must be
downstream of the heat exchanger. The cooled air
passing over the warm ambient air inside the heat
exchanger tubes can cause condensation inside the
tubes, resulting in corrosion and premature failure.

A parallel duct system can be installed to direct the air
from the furnace through the evaporator coil only. Use
dampers or other means to bypass the heat exchanger.
If [summer/winter] dampers are used, they should be
interlocked to prevent system operation unless the
dampers are in the full open or full closed position.

INSPECTION / ACCESS PANEL

If an air conditioning coil is not to be used in the supply air
plenum, it is recommended that the outlet duct be provided
with a removable access panel, which is accessible when
installed so the heat exchanger may be viewed for possible
openings using light assistance or a probe that can be
inserted for sampling the air stream. The access cover must
be fabricated in such a manner as to prevent leaks.

WARNING

WHEN INSTALLED IN THE COUNTERFLOW POSITION ON
A COMBUSTIBLE FLOOR, SUBBASE KIT #30476 IS
REQUIRED. FAILURE TO INSTALL SUBBASE KIT COULD
RESULT IN FIRE, DEATH OR SERIOUS INJURY.

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