Goulds Pumps AF (Axial Flow) (6"-36) MXR Bearings" - Manual (Page 44)

42 AF (6-36) IOM
Pump Troubleshooting
PROBLEM PROBABLE CAUSE REMEDY
Pump not primed or prime lost, liquid level does not completely fill elbow Fill system piping completely so the impeller is submerged
Suction inlet clogged Remove obstructions from pump inlet
Impeller clogged with foreign material Back flush pump or manually clean impeller
Suction and /or discharge valve closed or clogged Open valves to remove shut-off condition
No liquid delivered or
intermittent flow
Wrong direction of rotation
Change rotation to concur with direction indicated by the arrow on the
bearing housing
Suction piping incorrect Replace or modify suction piping
Insufficient NPSH available Increase liquid level or lower pump
Air leak in suction line Test suction piping for leaks
Speed (rpm) too low New drive or gear box to obtain higher pump speed
Excess air entrapped in liquid Install vent in piping or eliminate air source
Impeller partly clogged Back flush pump or manually clean impeller
Insufficient suction head Fill system piping so the liquid level is above the pump impeller centerline
Pump not primed or prime lost, pump does not completely fill elbow Fill system piping completely so the impeller is submerged
Suction and/or discharge valve closed or clogged Open valves to remove partially blocked condition
Suction piping incorrect Replace or modify suction piping
Pump not producing rated flow
or head
Excessive air entrapped in liquid Install vent in piping or eliminate air source
Speed (rpm) too low New drive or gear box to obtain higher pump speed
Incorrect rotation Check motor wiring
Incorrect impeller or impeller diameter Check vane angles and/ or impeller clearances
System head too high Check system curve calculations, reduce system resistance
Instruments give erroneous readings Check and calibrate instruments, replace if necessary
Worn or broken impeller, bent vanes Inspect and replace if necessary
Pump assembled incorrectly Compare pump assembly to instruction manual
Insufficient NPSH available Increase liquid level or lower pump
Wear of internal wetted parts
is accelerated
Chemicals in liquid other than specified
Analyze pumpage and correct or change pump wet end materials to suit
pumpage composition
Pump assembled incorrectly Compare pump assembly to instruction manual
Higher solids concentration than specified
Analyze pumpage and correct or change pump wet end materials to
harder composition
Packing gland improperly adjusted Tighten gland nuts
Excessive leakage Stuffing box improperly packed Check packing and re-pack box
from stuffing box Worn mechanical seal parts Replace worn parts
Overheating mechanical seal Check lubrication and cooling lines
Shaft sleeve scored Re-machine or replace as required
Pump run off design point Check head and flow, AF’s should be run at <75% BEP > 115%
Packing has short life Shaft/shaft sleeve worn Replace shaft or shaft sleeve if necessary
Packing gland not properly adjusted Replace packing and readjust gland as specified in the operating manual
Packing not properly installed Check head and flow, AF’s should be run at <75% BEP > 115%
Pump not assembled correctly Compare pump assembly to instruction manual
Table 4