User Guide
Pneumatic Control Manual 717.1
Comparators, Cumulators, and Relays Section
Product Bulletin C-2040
Issue Date 1184
© 1984 Johnson Controls, Inc. 1
Part No. 24-3415-2, Rev. A
Code No. LIT-7171410
C-2040 Averaging Cumulator
The C-2040 Averaging
Cumulator is a low volume
output device designed to
operate a controlled device or
receiver-controller by
averaging the output signals of
two, three, or four controllers
or transmitters. The C-2040
produces an output signal
equal to the average of the
input signals.
Operation
Inputs from up to four
controllers or transmitters are
applied to the pilot connections.
Supply pressure, through a
.007 in. restrictor, is furnished
to the supply/output port.
As the input pressure in any
of the pilot air chambers
increases, the exhaust port
will close until the output
pressure reaches the average
value of the inputs. On a
decrease in any of the pilot
pressures, the exhaust port
will open until the output
pressure drops to the
average value of the inputs
and the cumulator will again
be in balance.
Installation
The C-2040 is designed for in-
line mounting in any position.
Two #8 sheet metal screws are
furnished to secure the integral
mounting bracket to a panel if
desired.
The supply/output and exhaust
ports are marked “0” and “1”,
respectively. All connections
are made with 5/32 in. O.D.
polytubing to barbed fittings
furnished on the unit.
Note: Any pilot connections
not used must be plugged
with the caps provided.
The exhaust port of the
C-2040 must always be left
unplugged to avoid
overpressurizing the output
chamber.
Because of simplicity in
design, field calibration and
adjustments are not required.
Operational Checkout
Furnish supply and variable
input pressures to the C-2040
and check the output signal to
be sure that it is at the average
value of the inputs.
Repair Information
If the C-2040 fails to operate
within its specifications, unit
replacement is required; field
repairs cannot be made.
Note: When checking or
replacing the C-2040, 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).
Fig. 1: C-2040
Averaging Cumulator
Specifications