INTRODUCTION
The Cla-Val Model CDS7-DO Altitude Control
is a spring loaded, 3-way, diaphragm-actuated
control that provides high-level shut-off for Cla-
Val Altitude Control Valves. It remotely senses
pressure in the reservoir or tank. The DO fea-
ture provides an integral Delayed Opening
function for independently adjusting the dis-
tance between the high and low water level.
There are two altitude ranges available, 5 to 40
feet and 10 to 80 feet. The spring adjusting
screw can be set to stop flow into the reservoir
within these ranges. There is one delayed
opening range available: 1 - 16 feet.
INSTALLATION
The CDS7-DO Altitude Pilot Control is normally
supplied mounted on a Cla-Val 211 Series Altitude Valve which should
be installed in a horizontal run of pipe with the main valve cover up.
Two line block valves are recommended for valve servicing. If the
CDS7-DO is mounted from the main valve by a few feet, then it must
be installed with adjustment springs up for ease of adjustment and ser-
vicing. Consult factory for recommendations.
After the Cla-Val 211 Series Altitude Valve is installed in the pipeline
close to the reservoir, install the required remote sensing line from the
CDS7-DO to the reservoir or tank. The sensing line allows the CDS7-
DO to sense the static pressure head of the reservoir. The sensing line
should not be installed in the flowing line between the valve and the
reservoir or into turbulent flow area. These locations do not reflect the
true static head of the reservoir.
The remote sensing line should be 3/4" or larger copper tubing or
Schedule 40 PVC pipe. Galvanized pipe is not recommended. The
sensing line should slope (minimum 2 degrees) upward from the
CDS7-DO toward the reservoir to self-purge air out of the line. The
sensing line should have no high points to entrap air. A shutoff valve at
the reservoir connection is recommended. For above ground reser-
voirs, the connecting point for the sensing line should be a minimum of
12" to 18" above reservoir bottom (if filling from bottom) or at fill pipe
connection (if filling from side). Minimum high-level set-point adjust-
ment is approximately five feet above the remote sensing point of con-
nection.
Note:
Please make sure to remove the plastic plug from the drain
port before putting the valve in service if pilot drains to atmosphere.
OPERATION, START-UP AND ADJUSTMENT
When the reservoir pressure (head) is lower than the setpoint of the
spring on the CDS7-DO Altitude Control ports "1" and "D" are intercon-
nected. This relieves the main valve cover pressure to atmosphere.
Line pressure then opens the main valve to start filling the reservoir.
Reservoir sensing pressure increases as the liquid level rises in the
reservoir. When the sensing pressure increases to the set point of the
CDS7-DO control spring, the control shifts interconnecting port "S" and
port "1". This pressurizes the main valve cover chamber and the main
valve closes.
By turning the lower adjusting screw of the CDS7-DO pilot, the liquid
level shutoff point will be changed. Turn the adjusting screw clockwise
to raise the liquid level shutoff point; counterclockwise to lower the liq-
uid level shutoff point. Follow the general operation and start-up
instructions regarding purging air from the valve control system.
ALTITUDE CONTROL WITH
DELAYED OPENING
CDS7-DO
MODEL
INSTALLATION / OPERATION / MAINTENANCE
300105-01
CDS7-DO
STOCK
NUMBER
ALTITUDE
RANGE
(FT H
2
0)
5 - 40
NUMBER
OF
SPRINGS
1
5
ALTITUDE
CHANGE
PER TURN
DELAYED
OPENING
RANGE (FT)
CHANGE
PER
TURN
1 - 16
1
