No job is perfect. All industrial equipment has the potential for failure and things going wrong. Here’s how to troubleshoot the most common issues that happen with pumps and pump equipment. Sometimes pumps will wear out, often for a variety of factors. A lot of the wear and tear can be minimized through routine maintenance of critical components and replacing them when a problem is spotted.
No Liquid Being Pumped
|
| Potential Cause |
How to Fix |
| Pump is not primed |
Ensure pump and volute are completely full of liquid before operating the pump. If any air is trapped in the pump, it will not operate correctly. |
| Pump loses prime |
Check for leaks in the pump, pipeline, and couplings which could cause air to enter pump. If you suspect air in the pump, make sure to vent volute/casing to remove trapped air before resuming pumping. |
| Suction lift is too high |
Check pipeline for friction losses and ensure the static lift is not too high. If static lift is too high, you’ll need to lower pump closer to source material, or raise the material closer to the pump. |
| Suction line is clogged |
Remove obstruction |
| Static discharge head is too high |
Check pipe friction losses, use larger discharge pipes |
| Rotor speed to low |
Ensure the motor is receiving required voltage and correct frequency if using a variable frequency drive. |
| Rotor spinning wrong direction |
Check motor rotation direction as indicated by arrows on pump casing. Make sure the rotor is spinning in the correct direction when pump is in operation. |
| Rotor is clogged or jammed |
Disassemble the pump and volute to clear the rotor jam or clog. |
Flow Rate is Too Low
|
| Potential Cause |
How to Fix |
| Air leaks in suction hose |
If liquid pumped is water, test flanges for leakage with flame or match. For such liquids as gasoline, suction line can be tested by shutting off or plugging inlet and putting line under pressure. A gauge will indicate a leak with a drop of pressure. |
| Air leaks in stuffing box |
Increase the lubricant pressure to exceed atmospheric pressure, effectively locking air out of the stuffing box. |
| Cavitation |
Check NPSHr and NPSHa, you may not have enough positive suction head for what is required. |
| Defective rotor |
Open up pump and volute casing to inspect rotor for damages. If rotor has been damaged, ensure it is repaired or replaced prior to powering on the pump. |
| Defective packing |
Inspect and replace packing if sufficiently worn. |
| Rotor spinning wrong direction |
Ensure rotor is spinning in correct direction by comparing with indicator on volute. An rotor or impeller spinning in the wrong direction could damage the pump. |
Low Suction
|
| Potential Cause |
How to Fix |
| Clogged suction strainer or inlet |
Clean out strainer and ensure it is free from obstructions which could clog the suction inlet. |
| Insufficient hydraulic fluid |
Ensure pump motor is filled to proper hydraulic fluid levels. Consult the manual for your hydraulic equipment for proper fluid levels. |
| Leak in suction pipeline |
Inspect and repair pipeline for leaks |
| Insufficient suction pressure |
Raise liquid tank level closer to the pump |
| Worn check valves |
Clean or replace broken or worn out valves to ensure proper operation. |
Pump Motor Won’t Start
|
| Potential Cause |
How to Fix |
| Blown fuse or breaker |
Clean out strainer and ensure it is free from obstructions which could clog the suction inlet. |
| Starter overheating |
Correct cause of thermal overload and reset motor |
| Low line current |
Inspect lines and fix problem |
| Motor damaged |
Check for physical damage to motor, repair or replace as needed |
Pump Motor Overheating
|
| Potential Cause |
How to Fix |
| Operating motor in excess of rating |
Limit discharge pressure to max specified by motor manufacturer |
| Improper wiring or voltage too low |
Check power supply vs motor nameplate details for correct specs |
| Hydraulic oil too viscous |
Drain and refill with correct type of oil |
| High ambient temperatures |
Increase ventilation or relocate pump to cooler area |
Pump Periodic Maintenance Routine
|
| Daily |
Check Temperatures |
| Check cavitation & bearing noise |
| Check motor current and voltage |
| Weekly |
Check suction & discharge pressures |
| Check vibration & noise |
| Visual check for seal leakage |
| Monthly |
Remove safety guards and inspect pump shaft |
| Check for coupling alignment |
| Fill lubrication oil |
| Anually |
If pump is a spare, run the pump and check for any maintenance issues |
| Check for axial movement of motor shaft |
| Remove and clean all auxiliary components including valves, manometers, pipes and hoses |
| Remove couplings and inspect for wear on rubber parts |
| Every 2 Years or 10000 Hours |
Dismantle pump and inspect: Impeller, wear rings/plates, O-rings, pump shaft |
| Apply coating to un-machined surfaces |
