Comments no. 21 & 26: Why TI require only on Preheater Hot oil supply & return lines?
RE JST 8-12-2015: Comment 21 is for Preheater Hot oil supply, hot oil return and Steam condensate line. Comment 26 is for Preheater Steam supply line and Process supply line. 
TFS Reply: As per our calculation temperature drop across Preheater hot oil supply and return line is not more than 1 to 2 Deg C however in worst case scenario it is up to 40 Deg C. Why we have to measure hot oil temperature drop across preheater?
Why we need to measure the temperature of steam condensate line? 
RE JST 10-12-2015: In general, measurement of temperatures / changes in temperature are an indication that there is flow. In the past after draining and filling after maintenance we had problems with air pockets resulting in no flow, without knowing it. Hence, temperature measurements are required.
