Samson 43 Series - Page 15

EB 2172 EN 15
Customer inquiries
Type43-6
Possible reasons Recommended action
Temperature at the sensor exceeds the set point
Size (DN or G) of the valve is much too
small for the control task.
Recalculate K
VS
and select a larger valve.
Thermostat defective Replace thermostat (read specications on the nameplate).
Insufcient cooling energy available Draw up an energy balance.
Strainer blocked Drain and clean lter of the strainer.
Sensor installed in the wrong location. The entire length of the temperature sensor must be immersed in the
process medium and where idle times or heat buildup cannot occur.
Change mounting position accordingly.
Temperature at the sensor does not reach the set point
Leak at seat and plug Remove valve from the pipeline and clean seat and plug. Renew plug,
if necessary. If this is not possible, return regulator to SAMSON for re-
pair.
Valve too large for control task Recalculate K
VS
and select a smaller valve.
A safety device (e.g. STL, STM etc.) has
been triggered.
Check plant. Unlock safety device.
Control loop hunts·Very long dead time/sluggish control response
Size (DN or G) of the valve is much too
large for the control task.
Recalculate K
VS
and select a smaller valve.
Time constant is too large for the control
loop.
Fill the thermowell with thermal paste, remove thermowell or use sensor
with smaller time constant.
The valve is not installed in the direction
indicated by the arrow.
Install the valve in such a way that the ow of direction corresponds
with the direction indicated by the arrow on the valve body.
Sensor installed in the wrong location. The temperature sensor may be installed too far from the area where
the temperature to be controlled arises. Locate the sensor closer to heat
exchanger.