Cylinder/Motor Operates Without Remote Controller Being Operated; Cylinder/Motor Responds Slowly To Remote Electrical Or Hydraulic Controller Actuation; Erratic Cylinder/Motor Response To Electrical Or Hydraulic Controller Operation - Danfoss PVG 32 Service Manual

Service Manual
PVG 32 Proportional Valve Group
System Troubleshooting
Cause
Cylinder/motor load too high for
pressure settings of system

Cylinder/motor operates without remote controller being operated

Cause
Spool control tension rod loose
Electrical feedback transducer not in
neutral position
Remote electrical controller neutral
position switch faulty
Sticking pressure control valve in remote
hydraulic controller
Sticking main spool in valve section
Internal fault in the PVE/PVEH/PVEM/
PVEO
Contamination in the hydraulic oil

Cylinder/motor responds slowly to remote electrical or hydraulic controller actuation

Cause
Insufficient system pressure
Main spool travel limited
Incorrect signal voltage from
electrical controller
Incorrect hydraulic pressure signal
from remote hydraulic controller
Insufficient pilot oil - all sections
Insufficient LS pump stand by
pressure
Flow is not load independent

Erratic cylinder/motor response to electrical or hydraulic controller operation

Cause
Electrical actuator faulty
Main spool centering spring
damaged
© Danfoss | February 2017
Check
Check load pressure at PVB-LS port
Maximum system pressure should be approx. 25
Bar [365 PSI] above highest load pressure
Adjust pump pressure compensator setting if
necessary
Check
Confirm torque on spool control tension rod
Check the feedback pin in the PVE. It should be loose
Disconnect the connection at the PVE. It should come back to
neutral
Disconnect the hydraulic signal line from valve
Remove manual, electrical, and hydraulic actuators from the
valve section. Remove main spool from valve section and
inspected for damage. If no damage reinstall the main valve
spool. Spool should move freely in the valve section bore.
PVEO check continuity. All other PVE, check LED (Red means
internal error)
Take oil samples to confirm
Check
Install pressure gauge and record pressure
Check stops on manual lever controller end for proper
adjustment.
Refer to Component troubleshooting
Check the signal voltage from the controller with a
volt meter
Check pressure from the remote hydraulic controller -
25 Bar [360 PSI]
Check pilot for contamination and correctly
assembled parts - 10-15 bar [145-218 psi] Electric - 25
bar [360 psi] Hydraulic
Check pilot PSI - 10-15 bar [145-218 psi] Electric - 25
bar [360 psi] Hydraulic
PVLP check for cracks
Check LS pressure vs load pressure
Check
Check signal from controller to PVE
Check tension rod for correct torque or damage
Corrective action
Reduce load pressure if exceeds maximum pressure limit
of the system
Adjust maximum system pressure if necessary
Corrective action
If pressure is low adjust pressure setting to valve
specification or pump manufacturers specification
Adjust the manual lever stops and torque the jam nuts to
8 Nm [70 lbf•in] Do not exceed maximum torque
section.
If signal voltage is incorrect repair or replace electrical
controller
If pressure is too low, repair or replace remote hydraulic
controller per manufacturers instructions.
Replace inlet module NOTE: Check with S-D TST
Adjust or replace pump
Replace valve
Corrective action
Repair or replace PVE
Torque to 8 Nm [70 lbf•in] or replace
Corrective action
Torque to 8 Nm [70 lbf•in]
Replace transducer
Repair or replace faulty switch or wiring at
remote controller
Repair or replace faulty remote hydraulic
controller
Replace the valve module and main spool if
any damage is found on the main spool
Replace faulty PVE/PVEH/PVEM/PVEO
Flush hydraulic system. Fill with clean
filtered oil.
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