Samson 3251 - Malfunctions; Troubleshooting Common Issues

EB 8052 EN 8-1
Malfunctions
8 Malfunctions
Read hazard statements, warnings and caution notes in the 'Safety instructions and mea-
sures' chapter.
8.1 Troubleshooting
Malfunction Possible reasons Recommended action
Actuator and plug
stem does not move
on demand.
Actuator is blocked. Put the control valve out of operation (see the
'Decommissioning' chapter) and remove the
blockage.
WARNING! A blocked actuator or plug stem
(e.g. due to seizing up after remaining in the
same position for a long time) can suddenly start
to move uncontrollably. Injury to hands or ngers
is possible if they are inserted into the actuator or
valve.
Before trying to unblock the actuator or plug
stem, disconnect and lock the pneumatic air
supply as well as the control signal. Before
unblocking the actuator, release any stored
energy in the actuator (e.g. spring compression).
See associated actuator documentation.
Diaphragm in the actuator
defective
See associated actuator documentation.
Signal pressure too low Check the signal pressure.
Check the signal pressure line for leakage.
Jolting movement of
the actuator and plug
stem
Version with adjustable
packing
2)
: packing
tightened too far
Tighten the packing correctly (see section
'Adjusting the packing' in the 'Installation'
chapter > 'Testing the installed valve').
Actuator and plug
stem does not stroke
through the full
range.
Signal pressure too low Check the signal pressure.
Check the signal pressure line for leakage.
Travel stop active See associated actuator documentation.
Incorrect setting of valve
accessories
Check the settings of the valve accessories.
Increased ow
through closed valve
(seat leakage)
Dirt or other foreign
particles deposited between
the seat and plug.
Shut off the section of the pipeline and ush the
valve.
Valve trim, particularly with
soft seat, is worn.
Replace seat and plug (see the 'Servicing'
chapter) or contact our after-sales service.