
12 EB 3003 EN
Operation
Note:
Only a valve balanced by a bellows
can be used for steam control appli-
cations.
Needle valve · If the regulator tends to hunt,
we recommend installing a SAMSON screw
joint with restriction (needle valve) at the
control line connection of the actuator.
Note:
Needle valves, condensation cham-
bers, excess pressure relief equip-
ment and compression-type screw t-
tings can be supplied as required.
These accessories are listed in
uT3095.
6 Operation
See Fig.1 on page7.
6.1 Start-up
ÎFirst start up the regulator after mounting
all parts.
ÎMake sure the control lines are open and
correctly connected.
ÎIf needle valves are installed in the con-
trol lines, open them before start-up.
Fill condensation chambers with the pro-
cess medium before start-up.
ÎOpen the shut-off valves slowly prefera-
bly starting from the return ow pipe
side.
NOTICE
Impermissible excessive pressure.
The diaphragm actuator can be dam-
aged.
The pressure at the actuator must not
exceed the nominal pressure by 1.5
times on testing the pressure of the
plant when the regulator is already
installed. Shut off any external con-
trol lines before performing a pres-
sure test.
Rinsing the plant · After lling the plant, rst
completely open the consumer and rinse out
the pipeline at full ow rate for several min-
utes. Roughly adjust the differential pressure
set point. Check the installed strainer (e.g. by
measuring the pressure drop). Clean the
strainer, if necessary.
6.2 Adjusting the set point
Type 42-24 · Adjust the required set point by
tensioning the set point springs at the nut
(17).
If small differential pressure set points are to
be adjusted, we recommend using a differ-
ential pressure gauge instead of the two
pressure gauges to monitor the pressure.
Turn the nut (17) clockwise to increase the set
point and counterclockwise to reduce the set
point.
Type 42-28 · Set point xed to Δp = 0.2,
0.3, 0.4 or 0.5 bar.
6.3 Decommissioning
Preferably close rst the shut-off valve on the
upstream side of the valve and then on the
downstream side of the valve.