Back Seal Test Unit

The BSTU provides a controllable pressure between 7 and 210 bar to be applied via the pressure out connection. The pressure developed is monitored by a transducer which may be connected to the subsea control unit if required, and also an ana- logue subsea gauge. The applied pressure may be switched off/locked in by means of the ram operated ball valve.


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All the components are mounted on an Aluminium base plate which should be secured to the host vehicle structure in an accessible location. There are no specific spatial orientation requirements. Hydraulic connections are 1⁄4” Swagelok male thread.

The ram is operated by an ROV spare bi directional function (210bar max). The supply pressure may be acquired anywhere suitable from the host vehicle circuit (210 bar max). The drain line should be connected as directly as possible to the ROV return circuit to minimise return line losses.

The tool is supplied in an offshore suitable plastic Explorer case with foam insert.



  • Manually Adjusted Pressure Relief Valve
  • Ram Operated Ball Valve (with reducing jet)
  • Depth Compensated Pressure Gauge Electronic Pressure Transducer Aluminium Mounting Plate
  • Supplied in offshore suitable transit case.