24
Pilot Operated Prop. DC Valve with VCD
 ®
Series D*1FP/FE Explosion Proof
Operation Manual
Parker Hannifin Corporation
MSG11-5715-718 D_1FP IECEX UK.indd 19.12.19
Regular maintenance is essential in prolonging 
the service life of the systems, and safeguards 
plant safety and operational availability. The fol-
lowing items must be checked at regular and 
short intervals:
•   Oil level in tank
•   Max. medium temperature
•   Max. surface temperature
•   Condition of the pressure uid (sight check, 
colour and smell of hydraulic uid)
•   Operating pressures
malfunction at hydraulic load runtime
- generally no function
- high frequent oscillation
- low frequent oscillation
- one way operation only
- speed variations at unchanging command
- different speeds depending on travel direction
- speed too low
- drifting without command
- poor dynamic
possible reasons for malfunction corrective actions
X hydraulic pump resp. motor defective replace hydraulic pump resp. motor
X X X X X X X drive overloaded reduce pressure resp. speed, increase valve size
X X X X X X X X valve contaminated clean pressure uid, lter / ush valve
X X X hydraulic uid too viscous / too cold change uid grade, provide operational temperature
X X X too low oil level within tank rell pressure uid
X X X lter contaminated replace lter
X X X X supply voltage too low keep supply voltage range
X supply voltage carries too much ripple reduce ripple
X X X command signal too low increase command signal
X command signal carries too much ripple reduce ripple
X X X X X contacts of central connector contaminated clean contacts / replace plug
X feed cable interrupted x feed cable
X X X X X X X wiring sequence incorrect correct wiring sequence
X X feed cable without shielding change cable grade
X pilot pressure too low or failed increase pilot pressure to min. 20 bar
X X X pilot pressure too low increase pilot pressure to min. 20 bar
X pilot pressure too low increase pilot pressure to min. 50 bar
•   Preload pressure of pressure vessel (if present)
•   No leaks at any system components
•   Condition of the lter elements
•   Condition of the hose lines
•   Cleanliness of components
After a certain period of service, the hydraulic uid 
must be replaced. The frequency of the change 
depends on the following circumstances:
•   Type and grade of pressure uid (ageing)
•   Filtration
•  Operating temperature and ambient condi-
tions
8. Trouble Shooting
Basis of troubleshooting is always a systematic 
approach.
 For suspect of a sluggish spool the valve 
may be ushed with clean pressure uid.
 Troubleshooting in a hydraulic system re-
quires detailed knowledge about function 
and construction of the system. Therefore 
the work may exclusively be performed by 
qualied personnel.
9. Accessories / Spare Parts
Accessories
The following accessories are available for the 
valve series D*1FP and D*1FE:
Mounting bolts see table on page 12.
Spare Parts
The following accessories are available:
Valve type NBR
D41FP SK-D41FP
D81FP SK-D81FP
D91FP SK-D91FP
D111FP SK-D111FP
Valve type NBR
D41FE SK-D41FE
D81FE SK-D81FE
D91FE SK-D91FE
D111FE SK-D111FE