Malfunctions; Troubleshooting - Samson EB 8015 EN Mounting And Operating Instructions

8 Malfunctions

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

8.1 Troubleshooting

Malfunction
Actuator and plug stem
does not move on
demand.
Jolting movement of the
actuator and plug stem
Actuator and plug stem
does not stroke through
the full range.
Increased flow through
closed valve (seat
leakage)
EB 8015 EN
Possible reasons
Actuator is blocked.
Diaphragm in the
actuator defective
Signal pressure too low
Version with adjustable
packing : packing
1)
tightened too far
Signal pressure too low
Travel stop active
Incorrect setting of valve
accessories
Dirt or other foreign
particles deposited
between the seat and
plug.
Valve trim, particularly
with soft seat, is worn.
Recommended action
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 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 section
'Adjusting the packing' in the 'Installation' chapter
> 'Testing the installed valve').
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' chapter)
or contact our after-sales service.
Malfunctions
8-1