Giant GP7150A, Operation Manual

Page: 9 / 12

9
PUMP SYSTEM MALFUNCTIONS
MALFUNCTION CAUSE REMEDY
The Pressure and/
or the Delivery Drops Worn packing seals Replace packing seals
Broken valve springs Replace springs
Belt slippage Tighten or Replace belt
Worn or Damaged nozzle Replace nozzle
Fouled discharge valve Clean valve assembly
Worn or Plugged relief valve on pump Clean, Reset, and Replace
worn parts
Cavitations Check suction lines on inlet
of pump for restrictions
Unloader Check for proper operation
Water in Crankcase High Humidity Reduce oil change intervals
Worn Seals Replace seals
Noisy Operating Worn bearings Replace bearings, Refill
crankcase oil with recommended
lubricant
Cavitation Check inlet lines for restrictions
and/or proper sizing
Rough/Pulsating
Operation with
Pressure Drop Worn packing Replace packing
Inlet restriction Check system for stoppage
air leaks, correctly sized
inlet plumbing to pump
Accumulator pressure Recharge/Replace accumulator
Unloader Check for proper operation
Cavitation Check inlet lines for restrictions
and/or proper size
Pump Pressure as
Drop at gun Rated,
Pressure Restricted discharge plumbing Re-size discharge plumbing to flow
rate of pump
Excessive
Leakage Worn plungers Replace plungers
Worn packing/seals Adjust or Replace packing seals
Excessive vacuum Reduce suction vacuum
Cracked plungers Replace plungers
Inlet pressure too high Reduce inlet pressure
High Crankcase
Temperature Wrong Grade of Oil Giant oil is recommended
Improper amount of oil in crankcase Adjust oil level to proper amount