14
EB 3003 EN
Maintenance and troubleshooting
Table 1:
Troubleshooting
Malfunction
Possible reasons
Recommended action
Differential
pressure
exceeds the
adjusted set
point
Insufficient pressure pulses on the actua-
tor diaphragm
Clean the control line and the screw joint
with restriction.
Leak between seat and plug due to wear
Disassemble the regulator and replace
damaged parts.
Pressure tapped at the wrong place.
Reconnect control lines at a different
place. Do not tap pressure at pipe bends
or necks.
Diaphragm defective
Replace the diaphragm (see section 7.1).
Valve too large for control task
Recalculate K
VS
coefficient. Contact
SAMSON.
Differential
pressure
drops far be-
low the ad-
justed set
point
Valve or K
VS
coefficient too small
Check valve sizing. Install larger valve, if
necessary.
Safety device, e.g. pressure limiter, has
been triggered
Check plant. Unlock safety device.
Control loop
hunts.
Valve too large
Check valve sizing. Select valve with
smaller K
VS
coefficient, if necessary.
No damping of the pulses as the restric-
tion in the screw fitting of the actuator is
too large or is missing.
Install suitable needle valve in the control
line at the actuator. Close this needle
valve until the control loop becomes
stable. Do not close the needle valve
completely!