59MN7C: Installation, Start-up, Operating and Service and Maintenance Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
18
A10491
Fig. 24 – Installation on Combustible Flooring
Leveling Legs (If Desired)
In upflow position with side return inlet(s), leveling legs may be used,
see Fig. 25. Install field-supplied, 5/16 x 1-1/2 in. (8 x 38 mm) (max)
corrosion-resistant machine bolts, washers and nuts.
NOTE: Bottom closure must be used when leveling legs are used. It
may be necessary to remove and reinstall bottom flash to install leveling
legs. To remove bottom closure panel, see Fig. 23.
To install leveling legs:
1. Position furnace on its back. Locate and drill a hole in each bottom
corner of furnace.
2. For each leg, install nut on bolt and then install bolt with nut in
hole. (Install flat washer if desired.)
3. Install another nut on other side of furnace base. (Install flat washer
if desired.)
4. Adjust outside nut to provide desired height, and tighten inside nut
to secure arrangement.
5. Reinstall bottom closure panel if removed.
A89014
Fig. 25 – Leveling Legs
Location Relative to Cooling Equipment
The cooling coil must be installed parallel with, or on the downstream
side of the unit to avoid condensation in the heat exchangers. When
installed parallel with the furnace, dampers or other flow control must
prevent chilled air from entering the furnace. If the dampers are
manually operated, they must be equipped with means to prevent
operation of either unit unless the damper is in the full-heat or full-cool
position.
FILTER ARRANGEMENT
Filter and Return Duct Sizing
There are no provisions for an internal filter in these furnaces. An
external filter rack is required and is purchased separately. A field
supplied accessory air cleaner may also be used in place of the filter
rack.
Pressure drop must be taken into account when sizing filters, filter racks,
IAQ devices, and associated system ductwork. See Table 7 for a
comparison of Pressure Drop (initial/clean resistance to airflow) versus
Airflow for a variety of filter media types and sizes. These are
representative numbers. Consult the filter or IAQ device manufacturers’
specification sheet for performance data for a particular filter media or
IAQ device.
The furnace may use an optional media filter cabinet. The optional
media filter cabinet uses either a standard 1-inch (25 mm) filter or 4-inch
(102 mm) wide media filter which can be purchased separately.
The optional media cabinet is sized for bottom return applications for
use in upflow, downflow and horizontal applications.
For upflow side return applications, the optional media cabinet (or field
supplied accessory air cleaner) can be installed on the side of the furnace
or side and bottom when a bottom plenum is used.
For downflow applications, the optional media cabinet (or field supplied
accessory air cleaner) must only be connected to the bottom opening on
the furnace, see Fig. 21 and Fig. 26.
For horizontal applications, the optional media cabinet (or field supplied
accessory air cleaner) for all models can be connected to the bottom
opening on the furnace. For side return use in the horizontal position,
refer to Fig. 22. If both side and bottom openings are used in Fig. 22,
each opening used will require a filter.
A filter rack or any filed supplied accessory air cleaner can also be
installed in the common return duct prior to entering the return air
opening in any orientation.
Refer to the instructions supplied with the Filter Rack or accessory air
filter for assembly and other details.
Due to the relatively high pressure drops of 1-in (25 mm) thick
after-market filter media, it is recommended that the filtration system be
designed for at least 2-in (51 mm) thick media.
TIPS FROM CONTRACTORS: Install a media cabinet capable of
incorporating a 4-in (102 mm) thick media filter. This allows room for
future upgrades to other IAQ devices.
PLENUM
OPENING
C
A
B
D
FLOOR
OPENING
DOWNFLOW
SUBBASE
SHEET METAL
PLENUM
FLOOR
OPENING
FURNACE
(OR COIL CASING
WHEN USED)
COMBUSTIBLE
FLOORING
APPROVED
COIL ASSEMBLY
OR
COIL BOX
FURNACE
SHEET METAL
PLENUM
FLOOR
OPENING
COMBUSTIBLE
FLOORING
1
3
/ 4″
1
3
/ 4″
1
3/
4″
1
3/
4″
5/
16″
5
/ 16″
5/
16″
5/
16″
(44mm)
(8mm)
(44mm)
(8mm)
(8mm)
(8mm)
(44mm)
(44mm)
WARNING
!
FIRE, CARBON MONOXIDE AND POISONING
HAZARD
Failure to follow this warning could result in fire, personal injury or
death.
Never operate a furnace without a filter or filtration device installed.
Never operate a furnace with filter or filtration device access doors
removed.
FURNACE
CASING
WIDTH
FILTER SIZE
FILTER TYPE
SIDE
RETURN
BOTTOM
RETURN
17-1/2 (445)
16 x 25 x 3/4
(406 x 635 x 19)
16 x 25 x 3/4
(406 x 635 x 19)
Washable
*
*. Recommended to maintain air filter face velocity. See Product Data for part
number.
21 (533)
16 x 25 x 3/4
(406 x 635 x 19)
20 x 25 x 3/4
(508 x 635 x 19)
Washable
*
24-1/2 (622)
16 x 25 x 3/4
(406 x 635 x 19)
24 x 25 x 3/4
(610 x 635 x 19)
Washable
*
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