Malfunctions; Troubleshooting - Samson 3256 Mounting And Operating Instructions

8 Malfunctions

Read hazard statements, warnings and caution notes in the 'Safety instructions and mea-
sures' section.

8.1 Troubleshooting

Malfunction
Actuator and plug stem
does not move on de-
mand.
Jolting movement of the
actuator and plug stem
Actuator and plug stem
does not stroke through
the entire range.
Increased flow through
closed valve (seat leak-
age)
EB 8065 EN
Possible reasons
Actuator is blocked.
Diaphragm in the actuator
defective
Signal pressure too low
Version with adjustable
packing : packing not
1)
tightened correctly
Signal pressure too low
Travel stop active
Incorrect setting of valve ac-
cessories
Dirt or other foreign parti-
cles deposited between the
seat and plug.
Valve trim, particularly with
soft seat, is worn.
Recommended action
Check attachment.
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
fingers 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.
See associated actuator documentation.
Check the signal pressure.
Check the signal pressure line for leakage.
Tighten the packing correctly (see information
under 'Adjusting the packing' in the 'Testing the
installed valve' section).
Check the signal pressure.
Check the signal pressure line for leakage.
See associated actuator documentation.
Check the settings of the valve accessories.
Shut off the section of the pipeline and flush the
valve.
Replace seat and plug (see the 'Servicing' sec-
tion) or contact our after-sales service.
Malfunctions
8-1