100l/min wow

are you sure its not 100l/hr. That might be your problem, what kind of pressure are you building?
I have two brand new MPS Pressure Sensors Delta 100.
Both of them are leaking internally,not at the fittings but at the internal gasket/sensor interface.Got them installed on two separate loops to monitor some filters. The water flow is about 100l/min on each loop, measured with MPS flow sensors witch are not leaking.
I can understand one to be defective, but two?
Tried swapping the tubes, tought maybe I got High/Low ports mixed, still leaks. Is something I'm doing wrong, or should I call for replacements?