The VZWD is a direct-operated 2/2-way poppet solenoid valve built for applications where pilot-operated valves cannot function — because there is no minimum pressure differential to drive them. It opens reliably from 0 bar, making it suitable for gravity-fed tanks, vacuum systems, and low-inlet-pressure process lines that most solenoid valves cannot handle.

Why does zero minimum differential pressure matter?

Pilot-operated solenoid valves use the media pressure itself to shift the main seal. When inlet pressure is near zero — during tank draining, vessel filling from an overhead source, or vacuum service — the pilot stage cannot build enough force to open. The VZWD eliminates this dependency: its electromagnetic actuator directly lifts the poppet off the seat, independent of line pressure. This makes it the reliable choice for open-atmospheric discharge, suction-side positioning, and any circuit where pressure conditions at the valve inlet are not guaranteed.

How does the DN size affect pressure and flow capacity?

The VZWD's poppet design creates an inverse relationship between orifice size and pressure rating. Smaller orifices withstand higher pressure because the solenoid force acts on a smaller sealed area. The table below maps this trade-off across the eight available DN sizes:

For applications needing both high flow and high pressure, two VZWD valves in parallel on a larger line may be more practical than a single oversized pilot-operated alternative that requires a minimum differential.

When should you choose stainless steel over brass?

Brass (CW617N, CRC 1) is suitable for neutral media in dry indoor environments. Choose the stainless steel variant (1.4305, CRC 3) when the medium is even mildly aggressive, when ambient humidity or washdown exposure is expected, or when paint-wetting impairment substances (PWIS) must be excluded — the stainless body is PWIS-free per VDMA 24364 Zone III. Both variants use FKM (fluoro rubber) seals, compatible with mineral oils and many synthetic heat-transfer fluids up to 80 °C.

What electrical options are available?

The VZWD accepts 24 V DC (11 W or 6.8 W low-power coil), 110 V AC (19 VA switching / 16 VA holding), or 230 V AC (18 VA / 15 VA). All versions use a square-pattern electrical plug to EN 175301-803, Type A, and are rated for 100% duty cycle with IP65 ingress protection. Switching times are 20 ms energizing and 18 ms de-energizing — fast enough for most open-loop fluid control tasks but not intended for high-speed cycling applications.