Emergency Action - Samson 3349 Mounting And Operating Instructions

Malfunction
Actuator and plug stem
does not stroke through
the entire range.
Increased flow through
closed valve (seat
leakage)
The valve leaks to the
atmosphere (fugitive
emissions).
Note
Contact our after-sales service for malfunc-
tions not listed in the table.

8.2 Emergency action

Plant operators are responsible for emergen-
cy action to be taken in the plant.
In the event of a valve malfunction:
1. Close the shut-off valves upstream and
downstream of the control valve to stop
EB 8048-21 EN
Possible reasons
Signal pressure too low Check the signal pressure.
Plug has become
detached.
Incorrect setting of
valve accessories
Dirt or other foreign
particles deposited
between the seat and
plug.
Valve trim, particularly
with soft seat, is worn.
Defective packing
Diaphragm not
correctly clamped into
position.
Diaphragm damaged.
Recommended action
Check the signal pressure line for leakage.
Fasten plug and plug stem together (see
section 9.4.2 and 9.5.2).
Check the settings of the valve accessories.
Shut off the section of the pipeline and flush the
valve.
Replace the plug (see section 9.4.2 or section 9.5.2)
or contact our after-sales service.
Replace the packing (see section 9.4.1 or
section 9.5.1) or contact our after-sales service.
Check that the diaphragm is correctly seated. If
necessary, replace the diaphragm (see section 9.4.2
or 9.5.2).
Check the tightening torque of the joint between
plug and plug stem.
Check the tightening torque of the joint between
body and bonnet/flange.
Replace the diaphragm (see section 9.4.2 or 9.5.2).
the process medium from flowing
through the valve.
2. Perform troubleshooting (see sec-
tion 8.1).
3. Rectify those malfunctions that can be
remedied based on the instructions pro-
vided here. Contact our after-sales ser-
vice in all other cases.
Putting the valve back into operation after
a malfunction
See section 6.
Malfunctions
39