Lead-Lag Operation Of Two Compressors; Subtractive Pilot View - Gardner Denver Electra-Screw EDEQHF Operating And Service Manual

Step
11:
When display shows dashes (---- ----):
a) Press "Stop-Reset" - the pressure display now
shows the current "zero" pressure for the final
discharge transducer in the left window, and
"PI" in the right window.
b) Press "Stop-Reset" again - this will zero the
circuit board on the final discharge pressure
transducer and move the display to the next
step. The left window will read the current
"zero" pressure for the oil reservoir transducer
and the right window will now read "P2."
c) Press "Stop-Reset" again - this will zero the
circuit board on the oil reservoir pressure
transducer and move display program back to
the normal setup mode. The display should
read "O"pressure in the left window, and ----
current sump temperature in the right window.
w
a
3
m
0
w
a!
R
1-
in
n
3
DOWNSTREAM PRESSURE
FIGURE 4-5
Step 12: Stop the compressor and disconnect, tag and
lockout the power supply to the starter.
Step 13: Move the circuit board slide switch back to the
"set" position (right). You may now proceed
with normal start up procedure.
NOTICE
A. To readjust, the slide switch must
be in the"+" position.
B. If procedure is repeated, the
transducer zero operation may
be bypassed by not pressing
"STOP-RESET" while the dashes
( ---- ----) are displayed.
C. To zero the transducer, discon-
nect the control lines to the trans-
ducers and press "STOP/RESET"
while the dashes are displayed .
ADJUSTING
SCREW
'd
, VENT
DIAP
UPSTREAM
LINE
REAM LINE
LEAD-LAG OPERATION OF TWO COMPRESSORS -
The Auto-Sentry S controller provides the capability of
true lead-lag operation without the need to purchase any
additional equipment and without complicated intercon-
necting wiring.
Follow these steps to operate two compressors in a
lead-lag arrangement:
Step 1: Program load and unload pressure setpoint
on both units to the same value. For example:
ComPressor "A' load at 92 PSI: unload at 100
PSI. ComPressor "B"load at 92 PSI: unload at
100 PSI. $ee page 6, this section, for complete
information on programming the setpoints.
WARNING
Operation at excessive discharge air
pressure can cause personal injury or
damage to equipment. Do not set un-
load pressure above the maximum
stamped on the unit nameplate.
ADJUSTING
SCREW
SPRING
DIAPHRAGM
VALVE
OPEN
UPSTREAM
LINE
I 1- DOWNSTREAM
LINE
FIGURE 4-6- SUBTRACTIVE PILOT (CLOSED)
FIGURE 4-7- SUBTRACTIVE PILOT (OPENED)
13-8-610 Section 4 Page 6