Service manual

23
H. TROUBLESHOOTING
MALFUNCTION
POSSIBLE CAUSE
REMEDY
Loss of Flow or Low
Capacity
System component
malfunction
Inspect all system components. Correct
any malfunctions. Insure that suction and
discharge lines are open and all valves
are in proper positions.
Pump not primed or vented
Check reservoir oil level and fill as
required. Vent air from pump.
Low pump speed
Insure driver is not overloaded. For belt
drives, insure belt not slipping. For
variable speed drivers or variable speed
intermediate devices, insure proper speed
is set.
Incorrect pump rotation
Correct direction of driver rotation.
Obstruction in piping
Inspect all system piping and valves.
Remove any obstructions.
Wear of rotors and/or
housings
Replace worn rotors, gears, and/or
housing(s).
System bypass
Check all system bypass valves, including
relief valve. Repair or replace as
required.
Insufficient inlet pressure
Remove obstruction. Clean suction
strainer or filter element.
Loss of Suction
Suction line closed,
blocked or leaking
Verify suction line valve is locked open.
Inspect suction line, especially joints.
Remove any obstruction and repair any
leaks. Clean strainer or replace filter.
Excessive viscosity
Reduce viscosity by heating pump and/or
system liquids.
Dirty suction strainer
Clean or replace strainer or filter element.
Wrong direction of rotation
Correct direction of driver rotation.
Low Discharge Pressure
Low liquid level in reservoir
Check liquid level in reservoir. Fill as
necessary.
Air in system
Insure pump is vented and suction lines
are full of liquid.
Worn rotors, gears, and/or
housing(s)
Replace worn rotors, gears, and/or
housing(s).
Obstruction in piping
Inspect inlet piping and suction valve(s).
Remove any obstruction(s).
Dirty suction strainer
Clean/replace suction strainer or filter
element.
System bypass problem
Check all system bypass valves for
leakage, including relief valves. Repair or
replace as required.