vb80-400 Stainless unloader

vb80-400 Stainless unloader

SKU: vb85-160_unloader

vb80-400 Stainless steel unloader
Pressure regulating valve (Unloader)

Designed to prevent pump overload issues on gun closure, the waterflow is discharged in bypass reducing the pressure in the system upstream of the valve.


60.0550.00 - 1/2 Bsp F - 1/2 Bsp F - 1276 gr - 45 oz 1
60.0550.50 - 1/2 Npt F - 1/2 Npt F - 1250 gr - 44,3 oz


  • Dynamic seals made up of O-ring and runner in teflon.
  • Optimized internal passages that guarantee reducedpressure loss.
  • Antirotation device of the piston positioned inside the valve and obtained by an hexagonal sector of the piston itself.
  • O-rings of the fittings positioned upstream to the thread: no risk of fittings ejected in case of overpressure.
  • Double feed connection.
  • Version with knob fitted with locknut for minimum working pressure adjustment.

Rated Pressure 400 bar - 40 MPa - 5800 psi
Permissible Pressure 450 bar - 45 MPa - 6500 psi
Rated Flow Rate 80 l/min - 21 USGpm
Rated Temperature 70 °C - 158 °F
Material Stainless steel 303

    1. The valve has been designed for a continuous use with water at a temperature of 60°C (140°F). It can work for short periods with water at the maximum temperature of 90°C (195°F) .
    2. When the valve is in bypass mode, this is the decrease of pressure that has to occur in the circuit downstream of the valve, in order that the valve can restore the working pressure in the system. The indicated figure is expressed as a percentage of the pressure setting (working pressure).
    3. If the valve is fed through the lower inlet port, the maximum flow rate is 40 l/min.
  • At gun closure vb80-400 unloader, relieves the pressure increase in the circuit downstream of the valve. This pressure increase is used to activate the valve and discharge all the flow in bypass. The value of the pressure increase cannot be calculated.  It depends on the correct setting of the valve (see PRESSURE ADJUSTMENT/SETTING) and on the layout of the system: flow rate, working pressure, length and characteristic of the tubes, closing time of the gun