DP level Measurement Issue


facing some issue in DP LT - go through following points

1- service - Hydrocarbon
2- two numbers of LT installed at same position on same tank
3- heat tracing is provided to LP side impulse tubing
4- one LT is not working another is perfectly fine in readings.
5- the one which is not working frequently have to flush from LP side , condensate observed every 1-2 hrs .

any solution ?



is impulse line tubing is same for both the LT’s ?
means same line/length/angle’s


Thanks sir for sharing some issues But i think isuues same lines/length



It is important to check the heat tracing of the wet leg of the DP level transmitter which is giving erratic readings or not working. Since wet leg is being frequently drained every 1-2 hours, it can only mean that the heat tracing is not working to keep the temperature of wet leg above the dew point temperature of hydrocarbon.

Usually, for such applications, the wet leg should be filled up to the level where condensing vapours cannot enter and condense on top of Wet leg liquid to influence the pressure exerted by wet leg column. By Sloping the impulse tubing little downwards to let the condensate drain back to the tank, such situations can be avoided.

Better option for such applications is to have extended diaphragm DP transmitter with chemical seal on high and low pressure sides/ extended diaphragm on the high pressure side and extended pressure repeater on the low pressure side.

Author - Saurabh Bhardwaj