In normal practice, it is not necessary to disconnect TOR-5 from the transformer when replacing the filters, provided the system is designed with proper isolation valves. The circulation loop can be shut off locally, the filter housing depressurized and opened, and the cartridge replaced while the transformer remains in service. This is an important feature for online systems, because it avoids disturbing operation and losing trend continuity. Only in very simple installations without bypass or isolation would a full disconnection be required.