Samson 2404-2, Mounting And Operating Instructions

Page: 51 / 76

EB 2540 EN 8-3
Malfunctions
Malfunction Possible reasons Recommended action Note
Control loop
hunts
K
VS
/C
V
of pilot valve too
large (after valve has
been replaced).
Î
Install pilot valve with
suitable K
VS
/C
V
coefficient.
–
The flow conditions in
the plant at the location
where the regulator is
installed are not suitable
for the regulator.
Î
Pipe reducers,
instruments and
diversions can change
the flow conditions
which may lead to an
instable control process.
Refer to the SAMSON
document TV-SK 17041
for minimum distances.
If this is the case, send a sketch
of the plant to SAMSON for a
thorough analysis.
K
VS
/C
V
of main valve too
large
Î
Resize the valve.
Replace main valve or
reduced the flow rate
(smaller K
VS
/C
V
coefficient).
–
Periodic excitation to
vibrate originating from
the plant
Î
Contact SAMSON.
Possibly change the natural
frequency, e.g. over a needle
valve when there is resonance
in the plant.
Contact SAMSON's After-sales Service for
malfunctions not listed in the table.
The malfunctions listed in section 8.1 are
caused by mechanical faults and incorrect
regulator sizing. In the simplest case, the
functioning can be restored following the
recommended action. Special tools may be
required to rectify the fault.
Exceptional operating and installation con -
ditions may lead to changed situations that
may affect the control response and lead to
malfunctions. For troubleshooting, the con-
ditions, such as installation, process medi-
um, temperature and pressure conditions,
must be taken into account.
SAMSON's After-sales Service can support
you in drawing up an inspection and test
plan for your plant.
Note
Tip