Table of Contents
Advertisement
.5
0
INCHES W.C.
INCHES W.C.
Fig. 198 — Typical Minihelic Gage
This gage is calibrated and zeroed in the vertical position at the
factory. If the gage is used in any other position, it must be
re-zeroed each time the position is changed. Gages with ranges
under 5 inches w.c. (1.24 kPa), or the equivalent, should be used
only in the vertical position.
If the Minihelic needs to be removed or replaced, after installation,
the gage may need to be zeroed before placing in operation. If re-
zeroing is required, firmly hold the case of gage with one hand and
unscrew the front cover with the palm of the other hand in a coun-
terclockwise direction. If difficult to loosen, place a small sheet of
rubber between the cover and the palm of the hand. Zero-adjust
screw is located behind the scale at the pair marked "zero." Use a
hex allen wrench and adjust until pointer is on zero. This must be
done with both pressure connections vented to atmosphere and the
gage oriented in the final mounting position. Replace cover.
CAUTION
Attempted field repair may negatively impact your warranty.
Recalibration or repair by the user is not recommended.
CALIBRATION CHECK
Select a second gage or manometer of known accuracy and in an
appropriate range. Use short lengths of rubber or vinyl tubing to
connect the high-pressure side of the Minihelic gage and the test
gage to two legs of a tee. Very slowly, apply pressure through the
third leg. Allow enough time for pressure to equalize throughout
the system and for fluid to drain. If a manometer is being used.
Compare readings. If the gage being tested exceeds rated accura-
cy, it should be returned to the factory for recalibration.
MAINTENANCE
No lubrication or periodic servicing is required. Keep case exterior
and cover clean. Occasionally, disconnect pressure lines to vent
both sides of the gage to atmosphere and re-zero the gage.
Filters
See Table 46 for filter data for flat filter section, angle filter sec-
tion, bag-cartridge filter section, and filter mixing box section. Fil-
ters are field supplied.
Air filters should be inspected regularly and changed when dirty.
Filter life can vary greatly from one unit to another, depending
upon the application and the amount of contaminants in the return
and ventilation air entering the air handler. Each job should be
evaluated and maintenance schedules established accordingly. At
a minimum, the filters should be changed at the beginning of the
cooling and heating seasons.
Although not a direct part of the air handler, outdoor air inlet
screens and/or grilles that may be present should also be checked
regularly and cleaned as necessary. They can easily become
plugged with debris, grease, or other contaminants, depending
1.0
1.5
2.0
upon their location. This reduces the availability of ventilation air,
which can contribute to indoor air quality problems.
All filter sections use adjustable blank-off plates to close off any
airway area not filled with filter media. Check blank-off plates to
prevent unfiltered air from bypassing the filters. Blank-off plates
must be on door side of unit.
BAG-CARTRIDGE FILTERS
Side loading bag-cartridge filter section can use either bag or rigid
filters, 6-in. to 30-in. deep, with 7/8 in. header. They will not
accept headerless rigid filters.
Face loading bag-cartridge filter sections can use either bag or
rigid filters and are loaded from the front of the section. These
sections use Puro
Frame holding frames located at the
1
downstream edge of the filter section for prefilters and bag/
cartridge filters. Cartridge filters without headers can extend
upstream of the holding frame by 24 inches. Cartridge and bag
filters with 7/8 in. header extend downstream of the filter section
with filter length limited only by the length of the plenum
following the filter section. Filter elements are retained in frames
by wire fastener clips. To replace filter elements, remove clips,
insert elements with bag or cartridge downstream and reinstall
clips. (See Fig. 199).
See Fig. 200 for typical track for bag-cartridge filter section used
on draw-thru unit.
Fig. 199 — Puro-Frame Holding Frame and
Filter Retaining Clips
AIRFLOW
2" PRE-FILTER
Fig. 200 — Track for Draw-Thru Bag Cartridge
1. Puro is a registered trademark of Purolator.
221
a39-2266
BAG
CARTRIDGE
7/8" HEADER
Filter Section
39-2267
Advertisement
Table of Contents
