PRODEM PRB 030 - Adjusting the Pressure-Adjusting Valve for Blow Power

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5.8. Adjusting the pressure-adjusting valve
For PRB150 and bigger model
2
3
4
5
1
1.
Pressure-adjusting valve
2.
O-ring
3.
O-ring
4. Backup ring
5.
Adjuster nut
The graphic shows only a general
view of the pressure-adjusting
valve. The position of the pressure-
adjusting valve may vary on
different hammer models.
The PRB150 ~ PRB700 hydraulic hammer have a pressure-adjusting valve to allow adjustment of the
operating pressure which have an effect on the blow power. The pressure-adjusting valve controls the
hammer’s drain pressure during the piston raising operation. By controlling the working pressure, the blow
power can be increased or decreased.
 To increase the blow power, turn the pressure-adjusting valve clockwise.
 To decrease the blow power, turn the pressure-adjusting valve anticlockwise.
The pressure adjusting-valve is set in the factory before delivery; if you need to reset it, follow instructions
below:
1. Loosen the adjuster nut (5) to enable the adjust valve to be turn.
2. Turn the pressure-adjusting valve (1) clockwise or anticlockwise as required.
3. Tighten the adjuster nut (5) to the prescribed torque (140 ~ 180 N·m)
4. The standard factory settings are as follows:
No. of turns open from the full-close:
 PRB150 2.0 ~ 2.5  PRB250 / 300 2.5 ~ 3.0
 PRB170 1.5 ~ 2.0  PRB400 / 500 3.0 ~ 3.5
 PRB200 2.0 ~ 2.5  PRB700 2.0 ~ 2.5