N95ESN: 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
Filter Arrangement
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.
For upflow applications, the filter can be installed on either side of the
furnace, the bottom of the furnace or any combination of side and
bottom of the furnace. (See Fig. 21)
For downflow applications, the filter rack (or field supplied accessory air
cleaner) must only be connected to the bottom opening on the furnace
(See Fig. 22)
For horizontal applications, the filter rack (or field supplied accessory air
cleaner) can be connected to the bottom opening on the furnace. For side
return use in the horizontal position, refer to Fig. 23. If both side and
bottom openings are used in Fig. 23, each opening used will require a
filter.
A filter rack or any field supplied accessory air cleaner can also be
installed in the common return duct prior to entering the return air
opening in any orientation.
Table 6 – Air Filter Selection and Duct Sizing - In. (mm)
Refer to the instructions supplied with Media Cabinet or accessory air
filter for assembly and other details.
Filter and Return Duct Sizing
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.
Design the filter and associated ductwork for the best match of pressure
drop versus filter size. Best practice usually chooses filter systems with
pressure drops under 0.2 in. W.C. (50 Pa), with the best blower electrical
efficiency and system airflow performance occurring with filter pressure
drops under 0.1 in. W.C. (25 Pa).
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.
TIP 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.
Provide duct transitions, as required, to smoothly transition airflow from
the return duct system to the filter (or IAQ device) to the furnace when
the dimensions of the ductwork or furnace return air opening do not
match the required filter or IAQ device dimensions. See the instructions
supplied with factory-accessory duct adapters.
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
*
*. Filters with a side return-air may have a different filter size. Measure the
filter to obtain the correct size.
SIDE
RETURN
BOTTOM
RETURN
14-3/16 (360)
16 x 25 x 3/4
(406 x 635 x 19)
14 x 25 x 3/4
(356 x 635 x 19)
Washable
17-1/2 (445)
(1) 16 x 25 x 3/4
(406 x 635 x 19)
(1) 16 x 25 x 3/4
(406 x 635 x 19)
Washable
21 (533)
(1) 16 x 25 x 3/4
(406 x 635 x 19)
(1) 20 x 25 x 3/4
(508 x 635 x 19)
Washable
24-1/2 (622)
(1) 16 x 25 x 3/4
(406 x 635 x 19)
(1) 24 x 25 x 3/4
(610 x 635 x 19)
Washable
NOTICE
!
Design the duct system FIRST to determine how much pressure drop
may be allowed in the filter system. See the Air Ducts section.
Excessive filter pressure drop often compromises system airflow and
duct performance, causes inadequate airflow to the furthest ends of the
duct system, as well as causes excess noise and higher than anticipated
electrical consumption.
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