Johnson Controls C-9500 User manual

Pneumatic Control Manual 717.1
Comparators, Cumulators, and Relays Section
Product Bulletin C-9500
Issue Date 1285
© 1985 Johnson Controls, Inc. 1
Part No. 24-1233-18, Rev. B
Code No. LIT-7171445
C-9500
Two-Position Pilot Cumulator
The C-9500 Two-Position Pilot
Cumulator is designed to switch
its output from zero to full input
pressure at a preselected
pressure. It provides
two-position output from a
proportional input signal.
The C-9500 features an
adjustable set point and
differential. The set point is
adjustable from 4 to 20 PSIG
(28 to 140 kPa) and is factory set
at approximately 9 PSIG
(63 kPa); the differential is
adjustable from 1 to 7.5 PSI
(7 to 52.5 kPa) below the set
point and is factory set at
approximately 1 PSI (7 kPa).
When the input pressure is below
the set point, the output will be
zero. When the input reaches
the set point, the output will
switch and become equal to the
input. Beyond the set point, the
output pressure will increase at a
1 to 1 ratio with a rising input
pressure.
Operation
In a typical application (see
Fig. 2), the input of the C-9500 is
connected to a proportional
controller and the output is
connected directly to the valve
actuator. As the controller
output pressure increases, the
output of the C-9500 remains at
zero until the controller output
pressure reaches the set point
of the C-9500. At that pressure,
the C-9500 snaps open and the
input is delivered to the output,
closing the valve completely.
After the controller completes its
cycle, its output pressure
decreases and the output of the
C-9500 also decreases. As the
controller output pressure
reaches 8 PSIG (56 kPa), the
pilot chamber of the C-9500
snaps closed and the output
goes to zero, opening the valve.
Note: The signal to the
C-9500 must be a high volume
signal; a low volume signal or
a situation where the output
line is very long may cause
the C-9500 to cycle. This
device is specifically designed
for direct mounting on the
controlled device (as
described in the installation
section) to keep its output
working capacity at a
minimum.
Application and Drawing
Identification
Fig. 1: C-9500 Two-Position
Pilot Cumulator
Specifications

2 C-9500 Product Bulletin
Installation
The C-9500 is designed for
direct mounting to the actuator
(it is simply hand tightened on)
and features a 1/8 in. NPT
output connection and a 1/8 in.
NPT barbed fitting for 5/32 or
1/4 in. O.D. polytubing. Only
one actuator can be controlled
by each C-9500.
For applications where the
output from the C-9500 is
connected to a low capacity
device (for example a C-5226 or
a P-7100), the maximum line
length must not exceed the
following:
5 ft (152 cm) for 5/32 in.
O.D. polytubing
3 ft (91 cm) for 1/4 in. O.D.
polytubing
Calibration (See Fig. 3)
When making field adjustments,
the set point must be adjusted
before the differential. Changes
to the set point will affect the
differential; however, the
differential may be adjusted
without affecting the set point.
Set Point Adjustment
1. Remove the bottom cap
from the cumulator body.
2. Using a screwdriver, rotate
the spring adjusting screw
clockwise to decrease or
counterclockwise to increase
the set point. One full turn of
the screw in either direction
will provide approximately a
2 PSI (14 kPa) change in the
set point.
3. In order to check the set
point, the output must be
dead-ended. With the bottom
cap opening blocked and an
X-200-140 Hypodermic
Needle Test Probe (ordered
separately) inserted in the test
point, determine and reset the
C-9500 to the desired set
point. When the desired set
point is obtained, replace the
bottom cap.

C-9500 Product Bulletin 3
Differential Adjustment
1. Loosen the locknut.
2. Using a screwdriver, slowly
rotate the differential
adjusting screw clockwise to
increase or
counterclockwise to
decrease the differential.
Turn the screw
approximately 1/8 of a turn
at a time.
3. To check the differential,
observe the pressure on the
output gage for the point at
which the pressure drops to
zero. When the desired
differential is obtained,
retighten the locknut.
The maximum differential is
obtained by slowly turning the
screw clockwise into the body
until it stops, then backing it out
1/8 of a turn. Note: The screw
will stop because it contacts
the valve disc. Be careful not
to force the screw down onto
the disc. Refer to Fig. 4 for the
approximate maximum
differential pressures obtainable
for each respective set point.
Repair Information
If the C-9500 fails to operate
within its specifications, unit
replacement is required; field
repairs cannot be made.
Note: When checking or
replacing the C-9500, be sure
that the change in output
pressure will not upset the
system and cause damage (for
example allow a coil to freeze,
burn out a heater, collapse
duct work).

4 C-9500 Product Bulletin
Notes
Controls Group
507 E. Michigan Street
P.O. Box 423 Printed in U.S.A.
Milwaukee, WI 53202