As per P&ID provided by you, the tag of the valve is PCV0125. Normally the set pressure of such a valve is ~more than 0.5 Kg/cm2. Please check the specification sheet of this valve and find its set pressure.
0.1 Kg/cm2 be the set point of ESD/heater shut down at low pressure.
There are many options to perform the leak test of the circuit;
1. The leak test can be performed by opening the bypass globe valve or main valve QV-0101 and isolating the valves of the PCV. Because you are exposing equal pressure upstream and downstream of the PCV.
2. Another option of performing the leak test is to attach a Nitrogen hose at 3/4″ RFG-V06699.
Hope you get the answer.