HYDRAULICS 1.31 Outlet section (PVP) (26) Ac Accumulator PP Pilot pressure LS Load sensing T Return to tank P Pressure 32 Main pressure relief valve (RV1-290 bar) 34 Pilot pressure regulator (14 bar) 33 Compensator (pressure raising spool) (10 bar) 69 Test point Function The closed centre provides for ultimate system protection and the provision of pilot pressure for the operation of the spools.