Cut off the tap after installation

 

Yes, it is necessary to cut or pinch the filling plug of the pressure gauges; since the gauges are airtight, there can be a pressure difference between the inside of the pressure gauge and the atmospheric pressure, distorting the pressure gauge reading.

By cutting or pinching the plug, both pressures are compensated, ensuring that the reading of the instrument is correct.

This phenomenon is especially noticeable in low pressure ranges, between zero and 1.6 bar, as well as in vacuum gauges.