Common Pump Problems and Troubleshooting Guide | DAE Pumps

Common Pump Problems and Troubleshooting Guide

May 24, 2018

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. Find new slurry pumps.

No Liquid Being Pumped

Potential Cause How to Fix
Pump is not primed Ensure the 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 the 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 the pipeline for friction losses and ensure the static lift is not too high. If the static lift is too high, you’ll need to lower the pump closer to the 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 the required voltage and correct frequency if using a variable frequency drive.
Rotor spinning the wrong direction Check the motor rotation direction as indicated by arrows on the pump casing. Make sure the rotor is spinning in the correct direction when the 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 the suction hose If liquid pumped is water, test flanges for leakage with flame or match. For such liquids as gasoline, the suction line can be tested by shutting off or plugging inlet and putting the line under pressure. A gauge will indicate a leak with a drop of pressure.
Air leaks in the 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 the pump and volute casing to inspect the rotor for damages. If the 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 the wrong direction Ensure the rotor is spinning in the correct direction by comparing it with the indicator on volute. A 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 the strainer and ensure it is free from obstructions which could clog the suction inlet.
Insufficient hydraulic fluid Ensure the pump motor is filled to proper hydraulic fluid levels. Consult the manual for your hydraulic equipment for proper fluid levels.
Leak in the suction pipeline or hose Inspect and repair pipeline or hose for leaks.
Insufficient suction pressure Raise the 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 the strainer and ensure it is free from obstructions which could clog the suction inlet.
Starter overheating Correct cause of thermal overload and reset the motor.
Low line current Inspect lines and fix the 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 the 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 the correct type of oil.
High ambient temperatures Increase ventilation or relocate pump to a 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 the safety guards and inspect the pump shaft.
Check for coupling alignment.
Fill lubrication oil.
Annually If the pump is a spare, run the pump and check for any maintenance issues.
Check for any axial movement of the 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.

Need Help?

Our team of engineers is standing by to help you with your next project. Call us at (760) 821-8112 or submit a request.

Need Help?

Our team of engineers is standing by to help you with your next project. Call us at (760) 821-8112 or submit a request.

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