Pressure Differential during flushing

[jrrocks]

thread403-368719

Why Pressure (Discharge-Suction)Differential during CHW pipe flushing is very less? In my case it is as low as 0.1 bar. (Calculated head for the same CHW network is 40 meters)
I believe, even if all valve are 100% opened, due to fittings and pipe surface, frictional losses will be present (but not low as 0.1 bar, i was expecting more).

 

[lukaiENG]

Are you flushing through your equipment/coils or do you have flushing bypasses? if you have bypasses the pressure will be significantly less.
How much flow are they pushing through the pipes? if it is a reduced flow then the pressure drop will be lower.
Are strainer baskets in place? Contractor may have removed/replaced with more open to decrease pressure drop and get more velocity through pipework.
How confident are you that your calculations are correct?

 

[ChasBean1]

Make sure the system is full, pressurized, and the expansion tank is online.