Specifications

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Caution:
Don’t adjust the pressure of the main relief valve at will. If the pressure is too high,
the hydraulic system and hydraulic component may be damaged. When maintaining
or using, if oil pressure isn’t the same as the standard value, on the basis of
JB/TT3300 test way, the professional serviceman should adjust the pressure
according to the following procedures:
(a) Screw the plug screw off the inlet port of the control valve, install a 25MPa oil
pressure gauge.
(b) Operate the tilt lever, measure the pressure when the oil pressure stroke to
the end.
(c) When the oil pressure isn’t the same as the standard value, twist the adjusting
nut, twist it clockwise, raise oil pressure, on the contrary, reduce oil pressure.
(d) After adjusting, tighten the nut.
Fig.6.1 Control valve
6.4 Control valve operation
(1) Middle position (See Fig.6.2)
The oil that is expelled from the main pump will pass the middle passage and be
back to fuel tank. This moment, the cylinder port A & B must be off.