L A 5 0 0 0 L I Q U I D A P P L I C A T O R O P E R A T I O N & M A I N T E N A N C E M A N U A L
26
3
Service Instructions
The three valves used in the hydraulic control assembly are screw-in cartridge type valves and are replaceable.
Each valve must be installed with the correct tightening torque to ensure proper operation. If the valve is
tightened above the specified torque value, the valve internals may be damaged causing the valve to stick.
Before installing a new valve, inspect the valve to ensure all O-rings are seated in their appropriate grooves and
have no damage, such as nicks or cuts.
Lubricate all O-rings with the oil being used in the hydraulic circuit. This will ensure that the valve can slide
into the cavity without dislodging or damaging the O-rings.
Screw in the new valve and tighten to the following specifications:
Troubleshooting
Valve
Cavity Label
Torque (Ft-Lbs) [Nm]
PV72-30 Flow Control
PV
33-37 [44.7-50.2]
Check Valve
CV1
24-26 [32.5-35.3]
Check Valve
CV2
33-37 [44.7-50.2]
Symptom
Corrective Action(s)
No flow from the pump
Engage the manual override on the flow control valve
and send hydraulic flow to the motor. If no pump output
is generated check the tractor hydraulic system for
adequate supply flow and pressure or check the pump
troubleshooting guide for pump evaluation.
No flow from the pump
Measure the resistance of the valve solenoid coil with an
ohmmeter. The nominal resistance of the solenoid coil
is 4.5 ohms. If the resistance rating is near zero or very
high, the solenoid may be damaged.
Unstable pump performance
Review controller settings. Valve is normally closed,
110Hz PWM frequency. Decreasing brake point and/or
increasing dead band tolerance settings incrementally
may help improve stability.
Unable to get agitation flow
Review controller procedure for pump operation for
manual control or methods for sending PWM signal
to the valve while no flow is being detected by system
flowmeters.
