Honeywell 11255 - Manual (Page 74)

74
Application Guidelines
Precision Pak XDH filters should be selected using
24” x 12” and 24” x 24” face sizes. This allows for
12” increments in height and width of the filter bank
and insures that replacement filters will be readily
available.
Precision Pak XDH filters should be installed with
pockets vertical wherever possible. It is acceptable
to install 24” x 12” face size filters with pockets hor-
izontal if necessary to meet the size requirements
of the filter banks.
VAV Systems
VAV systems can be designed using the full range
depth of Precision Pak XDH filters. Filter banks
should be sized so that the maximum rated flow at
design conditions falls within the published recom-
mended velocities. Precision Pak XDH filters in all
standard depths can be applied at any capacity
between zero flow and catalog-rated capacities.
Gasketed Headers
Precision Pak XDH filters installed in Flanders K-
Trac Filter Framing Modules or Sureseal Side
Access Housings require polyfoam gaskets on
opposite header sides to prevent air bypass.
To specify Precision Pak XDH filters with gasketed
headers, add suffix “S” or “H” to the model number.
Use “S” gaskets on the sides parallel to the pockets
and “H” for gaskets on sides perpendicular to the
pockets.
Prefilters
Properly selected bag filters without prefilters will
generally require changeout annually in typical
HVAC applications. Because of the frequent main-
tenance expense and increase in fan kW input
using prefilters, they are seldom recommended on
lower efficiency final filters. However, prefilters are
often used on 85% and 95% efficiency applications.
1.0 General
1.1 Medium and high efficiency self-supporting filters
shall be Precision Pak XDH extended
surface type as manufactured by Flanders.
1.2 Filter sizes, efficiencies and capacities shall be
as scheduled on the drawings.
2.0 Filter Construction
2.1 Filters shall be constructed of polyolefin micro-
fine synthetic media encased in a thin non-
woven polyester backer mat.
2.2 Open area on the filter face for air passage shall
be not less than 90%.
2.3 Flexible internal support stitching shall maintain
individual pockets in a controlled form under all
rated air flow conditions.
Stitching shall be
sealed with thermoplastic resin. Edges shall be
finished with a four-thread overlock stitch to pre-
vent air bypass.
2.4 Pockets shall be bonded to galvanized steel cas-
ings and assembled into a galvanized steel
header with reverse-hemmed edges for safety.
2.5 Headers shall be gasketed with polyfoam on
vertical sides to prevent leakage when installed
in framing modules or Side Access Housings.
2.6 Filters shall be UL 900 Class 2 listed.
3.0 Performance
3.1 Initial and final resistances shall not exceed the
scheduled values.
3.2 Media area must equal or exceed that of the
specified filter.
3.3 The average efficiency shall be as determined by
the ASHRAE Standard 52.1 test methods.
3.4 The manufacturer shall guarantee performance
as stated in its literature within tolerances as
outlined is Section 7.4 of ARI Standard 850.
Flanders - Foremost in Air Filtration
Corporate Headquarters, St. Petersburg, FL
Guide Specifications
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