HY-EHPR08-33 (Proportional Pressure Reducing/ Relief Valve)

A screw-in, cartridge-style, direct-acting, spool-type hydraulic pressure reducing/relieving valve, which can be infinitely adjusted across a prescribed range using a variable electric input. Pressure output is to DC current input. This valve is intended for use as a pressure limiting device in demanding applications.


The HY-EHPR08-33 free flow ① to ③ when no current is applied to the coil. When the coil is energized, ② is connected to ①. Increasing current to the coil will increase the control (reduced) pressure proportional. If pressure at ① exceeds the setting induced by the coil, pressure from ① relieved to ③.

Note: back pressure on ③ becomes additive to the pressure setting at a 1:1 ratio.

Technical specification (for application beyond these parameters, please contact with us).


Technical specification (for application beyond these parameters, please contact with us)



Installation position


Storage temperature (℃)

-20℃ to +55℃

Ambient temperature (℃)

-20℃ to +50℃


Hydraulic specification

Max. inlet pressure

207 Bar (3000 psi)

Rated flow

4.0 Lpm (1.05gpm),DP=6 bar (87psi), cartridge only,

① to ③,coil de-energized,

Flow path

Free flow: ① to ③ coil de-energized;

Reducing: ② to ① coil energized;

Relieving: ① to ③ coil energized.

① is not plumbed externally

Hydraulic fluid

Mineral oil, phosphate-ester


7.4 ~ 420 cSt


-40℃~+120℃, with NBR seals


HY08-3, see page H.1.2


Electrical specification

Max. Control current

12 VDC coils: 1.2 A

24 VDC coils: 0.6 A

For other voltages, please consult factory

Reducing/ relief pressure range

(from zero to max. control current)

0-26 bar (0 to 3750 psi)


Less than 3%

Dither frequency required

200 Hz

Step response

T on <30 ms; T off <12 ms



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