F90A,B
The F90 is equipped with two standard
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
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
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
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.
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