MEDENUS RSP 254, Operating And Maintenance Instructions Manual

Page: 23 / 52

23
© 05.2022
9.2 Safety Shut-Off Valve
Description of the error Possible cause Elimination
No internal tightness
in closed position
Actuator dirty or damaged
Check valve seat and valve plate (seal) for damage
and dirt
Pressure compensation valve (bypass
line) in the actuator dirty or sealing
elements damaged Check O-rings in the pressure compensation valve
or at the SSV spindle and replace them, if necessary
Replace the bypass line
SSV spindle cannot be
engaged
No pressure compensation at actuator
Perform pressure compensation by opening the
bypass ball valve until the SSV spindle can be pulled
SSV cannot be engaged
Difference between response pressure
and operating pressure or between
upper and lower response pressure is
too small
Correct response pressure settings consider
required re-engagement differential (see RSP 254 /
255 product overview)
Only in case of underpressure
switching: Diaphragm
in the control device defective or
incorrectly installed
Check diaphragm and replace it, if necessary
Pressure at the measuring point too
high or low (only with underpressure
switching)
Lower or increase pressure at measuring point to
operating value (GPR setpoint value)
Sluggishness of the trigger
mechanism due to dirt / wear /
damage
Service switching device and replace if worn-out
mechanically
Permissible
response pressure
group is exceeded
Irregularities in
response behavior
Difference between response pressure
and operating pressure or between
upper and lower response pressure is
too small
Correct response pressure settings consider
required re-engagement differential (see RSP 254 /
255 product overview)*
Diaphragm in the control device
incorrectly installed
Check diaphragm for irregular tension
Sluggishness of the trigger
mechanism due to dirt / wear /
damage
Service switching device and replace defective parts
if worn-out mechanically
Gas escapes through
breather line
Diaphragm clamping has become
loose
Diaphragm is damaged or has been
mounted incorrectly
O-ring sealing (item 35) dirty or
damaged
Check diaphragm for fastening, damage, and
correct fit
Check O-ring and replace it, if necessary
*) The pressure differences between GPR, SSV and system SRV must consider the response and
closing pressure groups as well as the re-engagement differentials of the devices in order to avoid
any unintended SSV switching.
Note