Samson 3251 - Page 67

EB 8052 EN 9-5
Servicing
Inspection and testing Recommended action to be taken in the event of a negative
result
Check to ensure that the actuator and
plug stem move smoothly.
Version with adjustable packing
2)
: tighten the packing
correctly (see section 'Adjusting the packing' in the
'Installation' chapter > 'Testing the installed valve').
If the actuator and plug stem 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.
SAMSON recommends the use of positioners with integrated
diagnostic rmware for valves used for on/off service. The
partial stroke test included in this software helps prevent a
shut-off valve normally in its end position from seizing up or
getting jammed.
If possible, check the valve's fail-safe
position by briey interrupting the air
supply.
Put the control valve out of operation (see the
'Decommissioning' chapter). Identify the cause for the
malfunction and rectify it (see the 'Troubleshooting' chapter).
1)
EXPERTplus valve diagnostics can help identify external leakage at dynamic sealing systems as well
as seat leakage in valve versions without balanced plugs while the valve is in use. EXPERTplus comes
as standard in the digital positioners (Type3730, TROVIS3730, Type3731, TROVIS3793,
TROVIS3797).
2)
See the 'Markings on the device' chapter