Series NKS-N, NKSP-N
Page
12
9520-021-en
Revision 17
TM 10477
Edition 05/2022
7
Operation
7.1 Initial commissioning
Normally, the valves have been tested for leaks with
air or water. Prior to initial operation check cover
screws. For tightening torques, see
Section 1.2
.
Unless otherwise agreed there could be
residual amounts of water in the flow section
of the valve. This could result in a possible
reaction with the medium.
To prevent leaks, all connection screws should be
retightened after the initial loading of the valve with
operating pressure and operating temperature.
For tightening torques, see
Section 1.2
.
7.2 Improper operation and their
consequences
♦
Do not operate the butterfly valve without valve
actuation. Otherwise the disc will be uncontrollably
set in motion by the medium flow.
♦
Butterfly valves with a hand lever should never be
abruptly opened or closed. This can lead to water
hammer effects.
♦
Dissipate thermal expansion volumes in shut-off
pipes.
♦
If the plastic swells up due to the effect of the
medium, this can result in the functional parts
jamming.
♦
Operation with solids leads to increased wear.
♦
Operation during cavitation leads to increased
wear.
♦
Non-observance of the pressure-temperature
diagram can lead to damage.
♦
There must be no foreign matter on the sealing
surfaces.
♦
Do not remove the seals on the body screws
914/1
without observing
Section 8.1.1
.
Risk of injury!
7.3 Shutdown
Before loosening the flange bolts:
♦
ensure plant to be free of pressure
♦
flush out medium
♦
observe safety regulations
Prior to starting any repair work, the valve is
to be thoroughly cleaned. Medium residue
may be in the valve even if it has been
properly drained and flushed.
After dismantling immediately protect the valve
against mechanical damage.
7.3.1 Additional advice for shut-off and
control butterfly valve with actuator
Ensure that a remotely actuated quarter-turn
actuator cannot be accidentally switched on.
Prior to dismantling, install support
507
, join using
existing hex. screw
901/1
.
See installation instructions in
Section 5.2.1
and the
drawing in
Section 4.4
.
8
Malfunctions
♦
Flange connection ball valve/pipe is leaking
Retighten the flange screws to a tightening torque
according to
Section 1.2
. If this does not remedy
the leak, the recommended torques may be
exceeded by 10%.
If this also fails to stop the leak, dismantle and
inspect the ball valve.
Dismount valve and repair.
♦
Stem passage leaking
Dismount valve and repair.
♦
Medium leaking at the partition between lower and
upper halves
Dismount valve and repair, probably the stem seal
is not tight.
♦
Valve does not switch
Has the locking plate been dismounted?
See
Section 5.2.1
.
Is the actuator supplied with power?
Has a directional control valve been correctly
connected?
Is there foreign matter in the valve?
♦
The bore of the valve is leaking
Wear at the valve actuation ?
Do limit stops have to be adjusted?
Is the shaft deformed?
Deformation, damage or wear to body lining or
disc?
