Oleodinamica Marchesini V0438/300 VAU 1/4 cross-line pressure relief valve

Oleodinamica Marchesini V0438/300 is the VAU 1/4 cross-line pressure relief valve with the actual supplier-selected 80–300 bar spring range and 1/4" BSP connections. The manufacturer prints the base row and finite spring table; the full calibrated code is selected on the supplier offer rather than generated. Its base component row specifies maximum flow 30 l/min and maximum operating pressure 350 bar.

The two relief elements limit pressure in both actuator or motor branches by cross-line discharge. Connect the V1/V2 passages as shown and mount close to the actuator to reduce connecting-line pressure losses.

The 80–300 bar range describes spring adjustment capability rather than a confirmed delivered preset. The catalogue standard-setting reference for this spring is 150 bar. The spring endpoint does not override the separately stated 350 bar component limit.

The body is zinc-plated steel with hardened and ground internals, standard BUNA-N seals and guided-poppet sealing with negligible leakage. The common size row gives a mass reference of 0.988 kg; no separately weighed calibrated spring execution is stated. Handknob and sealing-cap suffixes denote other adjustments and are not added to this screw-adjusted article.

The local technical PDF retains the complete relevant original manufacturer spread, including the applicable size row, spring or option legend, hydraulic diagram and drawing. Neighbouring executions apply only to their identified rows. Any 50 °C oil temperature and 30 cSt viscosity beside curves are test conditions, not operating limits.