Parker Hannin Corporation
Hydraulic Pump and Power Systems Division
Marysville, Ohio USA
Bulletin HY28-2708-02/SVC/EN | July 2019
Medium Pressure Axial Piston Pumps
P1/PD B-mod Service Information
57
Effect of Trouble Possible Cause Fault Which Needs Remedy
High wear in pump
Excessive loads
Reduce pressure settings
Reduce speeds
Contaminant particles
in uid
Improper lter maintenance
Filters too coarse
Introduction of dirty uid to system
Reservoir openings
Improper reservoir breather
Improper line replacement
Improper uid
Fluid too thin or thick for operating temperature range
Breakdown of uid with time/temperature/heating effects
Incorrect additives in new uid
Destruction of additive effectiveness with chemical aging
Improper repair
Incorrect parts
Incorrect procedures, dimensions, nishes
Unwanted water in uid
Condensation
Faulty breather/strainer
Heat exchanger leakage
Faulty clean-up practice
Water in makeup uid
Heating of uid
Excessive pump leakage
Recheck case drain ow and repair as required
Fluid too thin
Improper assembly, port timing
Relief valve
Set too low (compared to load or to compensator)
Instability caused by back pressure, worn parts
Compensator
Set too high (compared to relief)
Worn parts
Pump too large for
uid needs
Select smaller pump displacement
Heat exchanger
Water turned off or too little ow
Water too hot
Fan clogged or restricted
Efciency reduced by mud or scale deposits
Intermittent hydraulic uid ow
Reservoir
Too little uid
Improper bafes
Insulating air blanket that prevents heat rejection
Heat pickup from adjacent equipment
Trouble Shooting