Top 10 Pump Malfunctions And What To Do About Them

EDITED BY LOREN FAULKNER Whatever type of centrifugal pump you use, the precautions and preventive maintenance plans for aggregate dewatering pumps are relatively similar: Know the Basics The solids-laden water at the bottom of a pit can quickly eat away at a pump. Choosing a pump that has solids-handling capability and hardened wear plate metallurgy will help combat wear patterns.

By Stephanie Morgan

November 05, 2007

EDITED BY LOREN FAULKNER

Whatever type of centrifugal pump you use, the precautions and preventive maintenance plans for aggregate dewatering pumps are relatively similar:

Know the Basics

The solids-laden water at the bottom of a pit can quickly eat away at a pump. Choosing a pump that has solids-handling capability and hardened wear plate metallurgy will help combat wear patterns. While a regular maintenance schedule is the best insurance policy, fundamental startup and handling procedures will also help prolong the life of a pump:

Change the engine oil and filter after the first 100 hours.
When preparing for cold weather, drain the discharge line and volute so that the suction line and volute drain enough to prevent damage to the volute, wearplates and seals if any remaining water freezes and expands.
Consider removing the ejector ball in colder months to prevent freeze-ups by allowing the volute to drain automatically during unexpected engine shutdowns (note that this option may extend priming time). In addition, consider installing a volute drain hose that extends from the volute to below the waterline on the suction side so that the water column in the line can help re-prime the pump.
To prevent establishing suction directly from the bottom of a pit, where the most damaging material is commonly found, use a floating screen/strainer on your suction that enables solids to pass that are no larger that the manufacturer's published solids-handling size.
Do not move the pump with hoses attached.

(Editor's Note: Stephanie Morgan is a Technical Writer for Godwin Pumps. For more information on pump maintenance issues visit: www.godwinpumps.com.)

Problem	Solution
1. Pump does not start	• Check the power supply
	• Flush the pump clean
	• Remove any obstructions
2. Pump does not prime	• Check the lift distance
	• Reposition the inlet/piping
	• Remove any obstructions in the suction/strainer and/or ejector assembly
	• Replace the suction or discharge hose
	• Check for o-ring and gasket damage
	• Check the seat and valve for damage
	• Check the compressor drive and belts
3. Pump outputs insufficient product	• Check the suction/discharge gauge reading
	• Check and clear the strainer/screen
	• Check for kinked or damaged hoses
	• Shorten hose length or increase hose diameter
	• Reduce total dynamic head or revisit pump selection
	• Repair or replace the impeller
	• Adjust throttle/speed setting
4. Pump requires excessive power	• Check the impeller/pump body
	• Revisit pump selection
	• Adjust throttle/speed setting
	• Check and reset impeller clearances
5. Pump vibrates or overheats	• Check the impeller/pump body
	• Check and clear the strainer/screen
	• Repair or replace the impeller
	• Reduce excessive suction lift
	• Adjust throttle/speed setting
6. Pump has emulsified (milky) hydraulic fluid or seal housing oil	• Drain and replace fluid or oil
	• Rebuild/replace mechanical seal
	• Evaluate pump cycle down time
7. Fluid temperature is high (hydraulic pump)	• Top off with clean fluid
	• Replace a worn hydraulic motor
	• Check for obstructions
8. Fluid in the reservoir is low (hydraulic (pump)	• Locate and replace broken hydraulic line
	• Replace o-ring seal in quick-release coupling
9. Pressure relief valve is high	• Check for obstructions
	• Replace filter
	• Repair/replace quick-release coupling
	• Check and tighten all couplings
	• Re-adjust valve for 3,500 psi
	• Check hydraulic hose length
	• Check pump throughput
10. Motor protection trips (electric pump)	• Verify that the power supply matches the motor requirements
	• Allow the pump to cool down