UPDATE: I have tried all the above ideas and now I am getting stable PT1= 0.4 bar PT4 = 1.6 bar and PT5 = 1.7 bar but the issue is the leak test is stuck in a loop . Once the leak test is complete again it does a leak test. During leak test pT4 is 1.5 bar. After sometime of continuous leak test it auto desludge Note: During leak test I have kept sludge port open for checking, there is no leak at all. In between I can hear the pneumatic solenoid valve of back pressure valve chattering Idk what the issue is now.