Honeywell F90B - Manual (Page 4)

F90A,B SELF-CONTAINED COMMERCIAL ELECTRONIC AIR CLEANER
68-0103-6 Revised 11-07 4
The F90 is equipped with two standard light-emitting diodes
(LEDs) and one optional LED.
ON LED: Lights when the solid state power supply is
powered and operating normally.
CHECK LED: Lights if the F90 requires service or if the
test button is pressed.
WASH LED (if used): Lights when cell washing is overdue.
To understand the operating sequence of the F90, refer to
Fig. 3.
Determine Number of F90 Needed
The sizing procedure determines the number of F90s needed
for any application. The correct number required for a
particular application depends on:
—
type of contamination.
— number of occupants.
— volume of the room.
— use of the room.
— outdoor air quality.
1
AIR CLEANER IS POWERED.
2
FAN DRAWS CONTAMINATED AIR INTO
THE BOTTOM OF THE F90.
3
LARGE PARTICLES ARE CAUGHT IN
THE PREFILTER.
SMALL PARTICLES PASS THROUGH
THE PREFILTER.
4
SMALL PARTICLES REMAINING IN THE
AIR ENTER THE IONIZER SECTION.
IN THE IONIZER SECTION, SMALL
PARTICLES RECEIVE AN INTENSE
ELECTRICAL CHARGE.
5
THE SMALL CHARGED PARTICLES
ENTER THE COLLECTING SECTION
WHERE THEY ADHERE TO THE
COLLECTOR PLATES OF OPPOSITE
CHARGE.
CARBON FILTERS (IF USED) ABSORB
ODORS AND OTHER GASEOUS
CONTAMINANTS.
6
CLEAN AIR PASSES THROUGH THE
FAN AND IS DISCHARGED IN FOUR
DIRECTIONS INTO THE ROOM,
PARALLEL TO THE CEILING TO
CREATE A COANDA AIR FLOW
PATTERN.
M1527A
Fig. 3. F90 operating sequence.
This sizing information in the following Examples 1, 2, and 3
was generated using the ASHRAE Handbook of
Fundamentals, 1990 and the ASHRAE Standard 62-1989,
Ventilation for Acceptable Indoor Quality. These examples
simplify the sizing procedure for most applications. Use this
information as a guide; however, keep in mind that the F90
has different capacities for each fan speed (see
Specifications section).
The number of air changes per hour determines the number
of F90s needed. More air changes per hour than indicated
are unnecessary because the ASHRAE data from which
these examples were constructed is conservative. Fewer air
changes per hour can be compensated for by bringing in
more outdoor air to maintain low contaminant levels or
tolerating a partially cleaned atmosphere. Either may be
acceptable to some users.
Regardless of the method used for calculation, the
architectural features, lighting fixtures, sprinkler system,
ducts, and grilles in the room to be cleaned may influence the
number of F90s required. For ambient air cleaning, establish
a uniform airflow pattern throughout the entire space. When
there is a lack of mounting space, fewer F90s than indicated
may be installed. More F90s may be required for oddly-
shaped rooms that do not have even airflow.
If any questions should arise, consult your full-service
distributor Honeywell Commercial Air Products.
To calculate the number of F90s needed using occupant
load, refer to Example 2 (page 6).
To calculate the number of F90s needed using air changes
per hour and room volume, refer to Example 1 (page 5) or
Example 3 (page 6).
Choose Location
Mount the F90 on the ceiling near the center of the room. A
45° diagonal mounting prevents stale air build-up in corners
and may allow use of F90s at lower speeds. See Fig. 4. In
larger rooms, divide the area into sections and mount an F90
in the center of each section. In rooms requiring varying
levels of air cleaning, concentrate F90s where air cleaning is
required most. See Fig. 4.
NOTE: To assure even air distribution, the F90 draws air
into the bottom of the air cleaner and discharges air
in four directions as shown in Fig. 5. This Coanda
air flow pattern assures that the clean air is
distributed to all parts of the space. Also, if possible,
mount the F90 to aid the air circulation already
established in the room.