Sympton
Possible Cause
Solution
Oil leak between crankcase and
pumping section
Worn rod oil seals
Replace crankcase piston rod seals
Frequent or premature failure of
the packing
Cracked, damaged or worn plunger
Replace plungers
Overpressure to inlet manifold
Reduce inlet pressure
Material in the fluid being pumped
Install proper filtration on pump inlet plumbing
Excessive pressure and/or temperature
of fluid being pumped
Check pressures and fluid inlet temperature; be
sure they are within specified range
Pump runs but produces no flow
Pump is not primed
Flood suction then restart pump
Pump fails to prime
Air is trapped inside pump
Disconnect discharge hose from pump. Flood
suction hose, restart pump and run pump until
all air has been evacuated
Pump loses prime, chattering
noise, pressure fluctuates
Air leak in the suction hose or inlet
Remove suction line and inspect it for a loose
liner or debris lodged in the hose. Avoid all
unnecessary bends. Do not kink hose
Clogged suction strainer
Clean strainer
Low pressure at nozzle
Unloader valve is by-passing
Make sure nozzle is matched to the flow and
pressure of the pump. If the nozzle is worn,
replace
Incorrect or worn nozzle
Replace packing or valves
Worn packing or valves
Clean or replace valves
Pressure gauge fluctuates
Valves worn or blocked by foreign
bodies
Clean or replace valves
Seals worn
Replace Seals
Low-pressure
Worn nozzle
Replace with nozzle of proper size
Belt slippage
Tighten or replace with correct belt
Air leak in inlet plumbing
Disassemble, reseal and reassemble
Relief valve stuck, partially plugged or
improperly adjusted valve seat worn
Clean and adjust relief valve; check for worn or
dirty valve seats
Worn packing. Abrasive in pumped in
cavitation. Inadequate water
Install proper filter suction at inlet manifold must
be limited to lifting less than 20 feet of water or
8.5 psi vacuum
Worn inlet, discharge valve blocked or
dirty
Replace inlet and discharge valve
Pump runs extremely rough, pres
-
sure very low
Inlet restrictions and/or air leaks
Clean out foreign material
Stuck inlet or discharge valve
Replace worn valves
Water leakage from under manifold Worn packing or cracked plunger
Install new packing or plunger
Slight leak, oil leaking in the area of
crankshaft
Worn crankshaft seal or improperly
installed oil seal o-ring
Remove oil seal retainer and replace damaged
0-ring and/or seals
Bad bearing
Replace bearing
Excessive play at the end of the
crankshaft pulley
Worn the main bearing from excessive
tension on drive belt
Replace crankcase bearing and/or tension drive
belt
Water in crankcase
Humid air condensing into water inside
the crankcase
Change oil intervals
Worn packing and/or cracked plunger
Replace packing. Replace plunger
Loud knocking noise in pump
Cavitation or sucking air
Check water supply is turned on
Pulley loose on crankshaft
Check key and tighten set screw
Broken or worn bearing
Replace bearing
TROUBLESHOOTING
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