7
TROUBLESHOOTING
TROUBLESHOOTING
Component problems and circuit problems are often inter-related. An improper circuit
may operate with apparent success but will cause failure of a particular component with-
in it. The component failure is the effect, not the cause of the problem.
This general guide is offered to help in locating and eliminating the cause of problems by
studying their effects:
effect of trouble
possible cause fault which needs remedy
noisy pump
air in fluid
leak in suction line
leak at shaft seal
low fluid level
turbulent fluid
return lines above fluid level
gas leak from accumulator
excessive pressure drop in the inlet line from a
pressurized reservoir
suction line strainer acting as air trap
cavitation in
fluid too cold
pump or motor
fluid too viscous
rotating group
fluid too heavy
shaft speed too high
suction line too small
suction line collapsed
suction strainer too small
suction strainer too dirty
operating altitude too high
boost or replenishment pressure too low
replenishment flow too small for dynamic conditions
misaligned shaft faulty installation
distortion in mounting
axial interference
faulty coupling
excessive overhung loads
mechanical fault piston and shoe looseness or failure
in pump
bearing failure
incorrect port plate selection or index
eroded or worn parts in the displacement control
erosion on barrel
air in fluid
see above
ports and port
cavitation
see above
plate
high wear in
excessive loads
reduce pressure settings
pump and motor
reduce speeds
contaminant
improper filter maintenance
particles in fluid filters too coarse
introduction of dirty fluid to system
reservoir openings
improper reservoir breather
improper line replacement