8
Donaldson Company, Inc. © 1996
Figure 4
Filter Pressure Drop and Set Point Indicator Display
SET POINT INDICATOR
RED
AMBER
GREEN
12345
12345
12345
12345
12345
12345
FILTER PRESSURE DROP
123456
123456
123456
123456
123456
12345
12345
12345
12345
12345
12345
12345
12345
12345
12345
12345
12345
12345
12345
12345
12345
12345
12345
12345
12345
12345
12345
12345
12345
12345
P
NOTE
Use a fine point permanent marker to
write on strips.
7.5
6.0
4.5
3.0
1.5
1.2.2 Filter Pressure Drop (Figure 4)
A single window selectively displays the filter
pressure drop (
∆
P*) or the relative set points.
The pressure drop indicator is a ten segment light
bar. From left to right, the first six lights are GREEN,
the next two are AMBER, and the final two are RED.
This display indicates the amount of static pressure
required to move the airflow from the dirty air
plenum to the clean air plenum through the filter
media and through the tube sheet opening.
The display provides a near linear division of the
available static pressure. The filter pressure drop
indicator lights move from left to right in a bar
display. Each light indicates 3/4"
∆
P. One light is
illuminated at a time to indicate the relative position
within the range.
1.2.3 Set Point Indicator (Figure 4)
When using the set point adjustments window, the
bar display switches to a set point display with one
or two lights illuminated. When one light is lit, the set
point is indicated. When two lights are lit, the set
point is bracketed by the two lights (half step).
In Sections 1.2.1, 1.2.2, 1.2.3 and Figures 3 and 4
are descriptions and pictures of two of the windows
located on the cover of the Checker board
enclosure. Packed with the enclosure are two
stickers (1/4" X 4"). These stickers may be used to
indicate airflow in cubic feet per minute. These
measurements can be determined during start-up
and calibration (Section 4.0 Start Up / Calibration
and Adjusting).
Wipe the surface of the control box to remove any
dust. Apply one sticker just below the LEDs on the
Airflow Window.
Write in the appropriate airflow as measured in the
system (see Figure 3). Airflows shown on Figure 3
are shown as an example only.
1.2.4 Blower ON/OFF (Figure 5)
The Blower window has a blower indicator light
(GREEN) and two push buttons. The green ON push
button provides power to the pull-in coil of the blower
motor starter. The light in this panel indicates the
switch closure only. The red OFF button disengages
the power to the motor starter pull-in coil and turns
off the indicator light.
*
∆
P=Pressure drop across filter elements in inches
water gage.
