Pressure Switch for Pump Trips

Usually, I use the low pressure on the pump discharge to indicate a problem downstream (like a line rupture or valve open that shouldn't be open in a particular step) and to keep the pump running on the pump curve. So, to answer your question as to a proper set point and time, you need to have a look at the pump curve for your pumps.

Follow the curve out to the right and have a look at the lowest pressure when the pump is running out on the curve (post a curve or pump model / impeller size and we can point it out). Take this pressure and provide an appropriate safety factor (I usually use about 50%, but that is for simple water distribution systems – it really depends on your system and how flat the pump curve looks).

Allow about 5 to 10 seconds for pump start and be sure you have a way for the operator to reset the system so the pumps can be started again (don't laugh, I had a PLC programmer forget this little requirement and we couldn't restart the pumps).

Stephan

Dear Stephen

Thank you for the valuable information. I will look in to the pump details and let you know the characteristics. The pump is installed in diesel filtration unit.

Thanks