Honeywell 11255 - Manual (Page 63)

63
Prefilters
Prefilters are always a wise choice for the protec-
tion of minipleat filters no matter what the efficiency
or brand. The closely-spaced pleats are subject to
face-loading (bridging) by lint and coarse particles,
thus reducing their usual long life. A minimum 25-
30% ASHRAE efficiency pleated panel filter such
as the Flanders Prepleat 40 is recommended.
Save In-Line Space
Compare the airway lengths of 22” PrecisionPak
bag filters and 12” Rigid-Air filter to a 4”
PrecisionCell filter when they are installed with 2”
prefilters.
VAV Systems
Filter banks should be sized so that the face veloc-
ity at maximum design conditions is 625 fpm or
less. PrecisionCell II filters may be applied at any
capacity between 0 and 625 fpm. Operating a filter
bank at reduced flow will greatly increase expected
filter life.
Save Storage Space and Shipping Costs
Using the 24” x 24” size as an example, a carton of
four PrecisionCell II 4” filters has a volume of 5.3
cubic feet and a weight of 26 lbs. Compare this to
four 12” deep rigid separator-type filters packed in
four cartons with a total volume of 16 cubic feet and
total weight of 80 lbs.
Application Guidelines
PrecisionCell II filters should be selected for new
installations with 24” H x 24” W and 24” H x 12” W
face sizes. These are the most widely used and
stocked sizes. This allows for 12” increments in
height and width of the filter bank and insures that
replacement cartridges will be readily available.
PrecisionCell II filters should be installed with the
pleats vertical wherever possible. It is permissible
to install 24” H x 12” W face size filters with pleats
horizontal if necessary to meet the size require-
ments of the filter bank.
HEPA Prefilters
PrecisionCell II filters are ideal as prefilters for
Alpha Cell HEPA filters. Their light weight and 4”
depth make them an excellent choice for installa-
tion in the optional Prefilter Frame Assembly for the
Alpha Cell HEPA Filter Holding Frame or in
Surelock Side Access HEPA Housings.
Specify the Surelock housing with an optional 4”
wide prefilter track for the PrecisionCell II filters, in
lieu of the 2” wide prefilter track for pleated panel fil-
ters. We recommend the selection of 80-85%
PrecisionCell II filters as HEPA prefilters.
Type 9 Frame with
PrecisionPak and Pre
Pleat 40
Type 9 Frame with
PrecisionCell II and
PrePleat 40
Sureseal Housing with
12” Rigid-Air and
PrePleat 40
Surepleat Housing with
PrecisionCell II and
PrePleat 40
Flanders - Foremost in Air Filtration
Corporate Headquarters, St. Petersburg, FL
the filter and hvac store