Table of Contents
Servicing
Inspection and testing
Check the test connection and bellows
seal (if used) for external leakage.
WARNING! Risk of personal injury due
to pressurized components and process
medium being discharged. Do not
loosen the screw of the test connection
while the valve is pressurized.
Check the valve's seat leakage.
Check the valve for external damage
(e.g. corrosion).
Check the valve accessories to ensure
they are mounted properly.
Check to ensure that the actuator and
plug stem move smoothly.
If possible, check the valve's fail-safe
position by briefly interrupting the air
supply.
See the 'Markings on the device' section
1)
9-4
Action to be taken in the event of a negative result:
Put the control valve out of operation (see the
'Decommissioning' section). To repair the bellows seal,
contact our after-sales service (see the 'Repairs' section).
Shut off the section of the pipeline and flush the valve to
remove any dirt and/or deposited foreign particles between
the seat and plug.
Replace the seat and plug (see section 9.4.4)
Repair any damage immediately. If necessary, put the
control valve out of operation (see the 'Decommissioning'
section).
Tighten the connections of the valve accessories.
Version with adjustable packing
correctly (see information under 'Adjusting the packing' in
the 'Installation' section > 'Testing the installed valve').
Unblock a blocked actuator and plug stem.
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.
Put the control valve out of operation (see the
'Decommissioning' section). Identify the cause for the
malfunction and rectify it (see the 'Troubleshooting' section).
: tighten the packing
1)
EB 8061 EN
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