Pump bypass valve H30, H300


  • Mechanically – hydraulically actuated valve
  • Pump bypass valve consisting of the 2/2-way valve and the non-return valve
  • Pilot valve as a separate unit to be attached to the pump bypass valve
  • Control pcb with fi lter inserts in an intermediate plate design
  • The valve seats seal hermetically preventing internal leaks
  • All parts are made of corrosion-resistant materials, and they are easily replaceable
  • Attachment, fl ange design to be mounted directly to pumps


Control function

The pump bypass valve, the control pcb and the pilot valve form a valve unit controlling a pump in a pressure supply system with a pressure accumulator. Depending on the system pressure, the valve controls the working cycle of the pump, „load accumulator“ or „depressurised bypass“. The P-connector is connected to the pressure port of the pump, the A-connector to the pressure line of the system and the T-connector to the pressure-free tank.

The flow of the pump enters the pump bypass valve at the P-connector. In the basic position, the pressure generated by the pump is used to close the 2/2-way valve (2) via the X- and the Z2-line. This has the effect that the non-return valve (1) opens, and the pump flow is supplied to the system via the A – connector.

At the pilot valve, the required pressure value „PE“ is set by means of the adjusting screw (3). Depending on the setting value, the springs (4) generate a force pressing the valve piston (6) into the valve seat (7). Thus, the Y-line is shut-off from the X- and Z2-line, and the generated pump pressure closes the 2/2-way valve. The pilot valve changes over, when the hydraulic power resulting from the pressure exceeds the power set at the springs (4) at the A- and thus at the Z1-connector. Then, the piston valve (5) lifts the valve piston (6) off the valve seat (7). Thus, the control surface of the 2/2-way valves (2) is depressurised, it opens and connects the lines „P, T“ with each other. Thus, the pump flow is carried pressureless to the tank. Simultaneously, the non-return valve (1) closes and shuts off the backflow from the system. The valve piston (6) remains in the open position until the system pressure at the A-connector falls short of the set pressure value „PE“ minus the value of the switching hysteresis; the 2/2-way valve (2) also remains open for this period.




Technical data

measured with HFA medium 97/3%, at 20°C


Weightsee Order information
Installation positionany
Ambient temperature-10 to 50°C (hydraulic fl uids, heed standard requirements)
Material Valve parts
Material Seals
Stainless steel, bronze


Pump bypass valve H30, H300

Hydraulic pressure connector P, A, M≤ 400 bar
Hydraulic pressure connector X, Z1, Z2≤ 400 bar
Hydraulic pressure connector Y≤ 10 bar
Direction of flowP->T, P->A

Pilot valve V300

Hydraulic pressure connector X, Z1, Z2≤ 400 bar
Hydraulic pressure connector Y≤ 10 bar
Pressure fluid
- Medium - Temperature range
- Medium - Quality
- min. filter fineness connection P, A, T
- min. filter fineness connection X, Z1, Z2
Water, HFA
5 to 40°C
see Hauhinco media requirement, water, HFA
Filter fi neness 100μm
Filter fi neness 25μm (control pcb with filter inserts)
Pressure fluid
- Medium - Temperature range
- Medium - Quality
Mineral oil HLP according to DIN51624-2
5 to 50°C
Cleanliness class -/19/16 according to ISO 4406
max. switching rate of the valve unit0,2 Hz
Note: The maximum decrease volume flow of the consumer and
the size of the pressure accumulator control the switching rate of the pump circulation control system.
Use of other pressure fluids on request.

Included in the scope of supply

Mounting screws of the valves


DescriptionNominal sizeWeightMax. pressureBasic positionVoltageNoteArticle number
Pump bypass valve H300DN2520,0kg400 bar6264956
Pump bypass valve H30DN3020,0kg400 bar6264948
Pilot valve V300/10DN10,0kg230-400bar (Einstellbereich)Switching hysteresis 10%5100682
Pilot valve V300/20DN10,0kg230-400bar (Einstellbereich)Switching hysteresis 20%5100658
Control pcb with filterDN3,0kg6328423

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