In some installations, a bypass is present to enable temporary supply during maintenance of the main regulator or train. Its use requires strict control.
Why a bypass exists
It allows for temporary maintenance of supply when a main section is taken out of operation.
Overpressure risk
If the bypass does not have proper regulation or is opened uncontrollably, higher pressure may pass downstream.
Manual operation
Manual regulation requires continuous monitoring of the downstream pressure and a clear procedure.
Normal status
After maintenance, the bypass must be returned to its intended status and the correct operation of the main train must be verified.