VDO Heavy Duty Normally Open–Single Circuit 4 PSI Pressure Switch

The VDO Heavy Duty Normally Open–Single Circuit 4 PSI Pressure Switch (MPN 230-404) is a precision marine electrical component designed for fuel system monitoring and pressure-dependent circuit activation in boats and recreational watercraft. This switch activates when system pressure reaches 4 PSI, making it ideal for fuel management systems, bilge pump controls, and water pressure applications where reliable pressure-triggered operation is essential to safe equipment operation.

Built with silver-alloy contacts for corrosion resistance and electrical durability, this normally open single-circuit switch operates across a 6–24V range, accommodating both 12V and 24V marine electrical systems. The two-terminal configuration simplifies wiring integration into existing marine control circuits. The #8-32 connection thread provides secure, standardized mounting on marine equipment enclosures and fuel system panels. At just 0.3 lbs and compact dimensions (5 x 1 x 8 inches), it installs easily in engine compartments and control boxes where space is limited.

This pressure switch is specified for weekend cruisers, offshore fishing vessels, and any boat requiring automated pressure-based system control. Weekend boaters appreciate its straightforward normally open design—no power required to hold the circuit open. Serious anglers and liveaboard operators rely on VDO's proven marine-grade engineering for fuel system safety and bilge automation during extended offshore operations. The switch's 4 PSI rating suits fresh-water and saltwater applications where precision and corrosion resistance directly impact system longevity.

VDO marine electrical components are OEM-standard across major boat manufacturers and are chosen by service technicians for their reliability under harsh marine conditions. This pressure switch replacement or upgrade component ensures consistent, pressure-responsive operation for years of trouble-free service.