Pilot Valves

Pilot Valves

The pilot valves main function is to operate larger valves from a remote location requiring less force.


Pilot valves control a reduced flow feed while sending it to another valve, that typically controls a high pressure/high flow feed. Furthermore pilot valves are useful because they allow a small and easily operated feed to control a much higher pressure/higher flow feed. Consequently enabling ease of use that would otherwise require a much larger force to operate. This is also useful when a solenoid is used to operate the high pressure/high flow valve. Finally the valve is made up of sections, each of which contains two 3-way pressure reducing signal ports. In addition up to 6 sections can be stacked into the same valve to give a total of 12 signal ports. The cast-iron valve housing and a hardened, precision-ground steel reducer-valve spool ensures a long service life with minimal internal leaks. Finally special low-friction seals give effective protection against external leakage as well.

Pilot Valves Essential Characteristics

  • Small dimensions enable simple, compact installation.
  • Robust, simple design gives great reliability and easy servicing.
  • Low, well-adapted lever forces and short lever strokes give good operating comfort.
  • Lever forces can be specified per control-pressure port to give function specific actuation resistance.
  • Low hysteresis gives consistent machine-function response to valve actuation.
  • Good metering properties enable gentle, proportional control.
  • Very wide range of control-pressure characteristics enables control of machine functions to be application-optimized.
  • Wide range of control devices and accessories gives great flexibility in system design.
  • Valve can be installed in arm rests of operator’s seat and fitted with site-suited lever to give very ergonomic control station.
  • Quality materials and great precision in manufacturing, assembly and testing assure a quality product with low internal leakage and long service life.
  • Total compatibility with Parker directional valves gives predictable and harmonious system characteristics.


  • The data given is applicable at an oil temperature of 50 ºC (122 °F) and viscosity of 30 mm2/s (cSt) using mineral base oil according to DIN 51524.


  • Supply pressure (pump pressure)……….max. 100 bar (1450 psi)
  • Recommended supply pressure……….15 bar (218 psi) higher than max. control pressure
  • Control pressure………max. 75 bar (1090 psi).
  • Breakaway pressure……….min. 1 bar (14.5 psi), max. 16 bar (232 psi)
  • Return-line pressure……….max. 3 bar (44 psi)

Flow rate

  • Control flow……….max. 15 LPM (4 US GPM)


  • Hysteresis……….max. 0.5 bar (7.3 PSI)

Hydraulic Fluids

    • Best performance is obtained using mineral-base oil of high quality and cleanness in the hydraulic system.
      HLP hydraulic fluids (DIN 51524), automatic-gearbox oil type A and API CD engine oils can be used. Synthetic, fire resistant and environmentally friendly fluids can also be used. Please contact Ryan Hydraulic Service for further information about hydraulic fluids.


    • Viscosity, function range……….10-5000 mm2/s (cSt)
      • Viscosity, working range……….10-380 mm2/s (cSt)


    • Filtration should be arranged so that the Target Contamination Class 16/13 according to ISO 4406 is not exceeded.


    • Min. ambient temperature……….–40ºC (-40°F)
    • Max. ambient temperature……….+60ºC (140°F)
    • Min. oil temperature……….–20ºC (-4°F)
    • Max. oil temperature……….+70ºC (166 °F)
    • Temperature change……….max. 100°C/s., max. 212°F/s


    • From pump connection to tank connection with the spool in neutral position and a supply pressure of 40 bar (580 psi) max. cm3/min……….(1.22 in3)per control-pressure port