Answer / ramana

In boiler Drum level transmitter or level transmitter range
always put -600 to 0 other -900 to 0.Because the pressur of
LP side is always high aginst pressure of the HP side in
closed tank.

Answer / radha

this is called wet leg system,so you are telling range -600
to 0 means your drum distance between HP & LP 600 mm and HP
and LP legs both are filled with condensate(water)
continueosly but LP leg distance higher than the HP leg,so
LP side pressure will acting 600mmWC extra, compare with HP
leg pressure,so we have to eliminate that pressure LP
pressure 600mmWC
thats why -600mmWC = 4mA
0 mmWC = 20mA

Answer / automatic

the negative value used for wet leg level transmitter that
means, you have the HP side filled with a reference liquid,
a initialy you should entre the pressure value of this side
in considiration that's why when we isolate the transmitter
from the vessel we never drain the HP leg

Answer / mavdiyaamit@gmail.com

I allways -600 to 0 range is used because maximum vacuum pressure ranhe is -760 mmHg so not use in -900 to 0

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