10 MAINTENANCE TOOLS
•
Lapping tools and LAMPLAN diamond paste (1.213, 3.213, 6.213)
•
Lifting lugs.
•
Cryogenic and Oxygen grease type ORAPI CT830 (-40°C/+280°C) or CT1240 (-40°C/320°C).
11 TROUBLESHOOTING
PROBLEM
POSSIBLE CAUSE
CORRECTIVE ACTION
The disc does not
move (no lift)
Damaged diaphragm
Carry out maintenance to remove the diaphragm
and to overhaul the potential damaged parts.
Foreign material trapped in between a
moving part and fixed one.
Carry out maintenance to remove the part and to
overhaul the potential damaged parts.
Pilot sensing entry not connected
Connect the pilot sensing entry to the valve entry
or remote to the equipment.
Carry out maintenance to lap or to change the disc
and to lap or to machine the nozzle.
Damaged seat
e
g
a
k
a
e
l
t
a
e
S
t
n
e
n
o
p
m
o
c
h
c
a
e
f
o
s
e
c
a
f
r
u
s
t
c
a
t
n
o
c
e
h
t
t
c
e
p
s
n
I
Part misalignment
from the lower cover to the seat. Check also the
stem alignment and concentricity.
Disc hinge has not sufficient
articulation
Inspect the disc and stem hinge surface.
Incorrect discharge piping support
allowances or its weight supported by
the valve outlet flange.
Rearrange the support hardware. Install if drip
pan if necessary. Review the outlet piping
installation.
The disc does not
reseat
Carry out maintenance to remove the component and
overhaul any damaged parts
Foreign material
Upstream pressure drop too high.
Redesign the inlet piping to reduce the pressure
drop to less than the ½ blowdown value
The valve chatters The valve is oversized
Investigate what is the real process condition and
check the sizing with Trillium Flow Technologies
TM
.
The upstream pressure drop is too high
Sensing the pressure remote instead of through
the sensing ring.
74LP PRESSURE RELIEF VALVE
SARASIN-RSBD
™
30
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