Filter Arrangement; Filter And Return Duct Sizing - International comfort products F96VTN Installation Instructions Manual

Bottom Return Air Inlet
These furnaces are shipped with bottom closure panel installed in
bottom return- -air opening. Remove and discard this panel when
bottom return air is used. To remove bottom closure panel see Fig.
27 and 28.
Side Return Air Inlet
These furnaces are shipped with bottom closure panel installed in
bottom return- -air opening. This panel MUST be in place when
side return air inlet(s) are used without a bottom return air inlet.
Not all horizontal furnaces are approved for side return air
connections See Fig. 24. Where required by code, seal bottom
closure to furnace with tape, mastic or other durable sealing
method..
SCREWS (2)
Representative drawing only,
some models may vary in appearance.
1 Lay furnace on the back or side
2 Remove the two (2) screws that secure the bottom
closure panel to the furnace casing and remove the
panel
Fig. 27 - - Removing Bottom Closure Panel (2 Screws)
SCREWS (4)
BOTTOM
PLATE
Representative drawing only,
some models may vary in appearance.
1 Lay furnace on the back or side
2 Remove the four (4) screws that secure the bottom
plate to the furnace casing
3 Remove the bottom closure from the casing
4 Re--install the bottom plate to the furnace casing and
re--install the four (4) screws
Fig. 28 - - Removing Bottom Closure Panel (4 Screws)
22

Filter Arrangement

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.

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 5
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).
BOTTOM
CLOSURE
Design the duct system FIRST to determine how much
pressure drop may be allowed in the filter system. See the Air
Ducts
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.
A170123
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.
A170124
Specifications subject to change without notice.
WARNING
!
NOTICE
section. Excessive filter pressure drop often
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