8 COMMON CENTRIFUGAL PUMP PROBLEMS & HOW TO TROUBLESHOOT THEM
Centrifugal pumps are essential components in industries such as water supply, wastewater treatment, HVAC, food and beverage, chemical processing, and agriculture. Whether you’re using a 1 hp centrifugal pump at home or a high pressure multistage pump in an industrial facility, unexpected downtime can be costly. This guide provides a practical, field-tested approach to diagnosing and fixing the most common centrifugal pump problems, helping you ensure long-term reliability and efficiency.
Introduction: Why This Guide Matters
Centrifugal pumps are the workhorses of fluid transport systems. However, even well-engineered setups can experience failures if pumps are not properly commissioned, operated, or maintained. From a self-priming centrifugal pump that fails to re-prime to a high pressure multistage pump tripping due to overload, many of these issues are predictable—and preventable.
This guide will help you:
- Quickly identify symptoms and root causes
- Apply safe and effective troubleshooting steps
- Select more reliable types of centrifugal pumps
- Minimize downtime and extend equipment lifespan
How to Use This Troubleshooting Guide
- Follow a logical sequence: begin with simple checks, then proceed to deeper diagnostics.
- Use the step-by-step diagnostic approach in Section 4 as a structured checklist.
- Document each incident: symptoms, pressure readings, flow rates, actions taken.
- Always prioritize safety: follow Lockout/Tagout (LOTO) procedures, wear appropriate PPE, and confirm motor rotation before startup.
Eight Common Centrifugal Pump Problems and Fixes
Includes:
- Pump fails to start or prime
- Low flow or no discharge
- Excessive vibration or noise
- Overheating
- Leakage
- Cavitation
- Loss of prime
- Reduced pressure or head
Systematic Troubleshooting Workflow
- Verify power and safety (voltage, phase, LOTO)
- Observe symptoms (noise, vibration, temperature, flow, pressure)
- Confirm proper priming and fluid flow
- Inspect mechanical components (impeller, seals, bearings, coupling)
- Check suction/discharge valves, piping, and filters
- Measure key performance parameters (flow, pressure, power, speed)
- Compare actual operation to the pump performance curve
- Implement corrective action and retest
Tools, Meters, and Safety
Essential tools include:
- Pressure and vacuum gauges
- Clamp meter, tachometer, infrared thermometer
- Vibration meter, alignment tools, seal pullers
Safety reminders:
- Always perform LOTO before servicing
- Wear gloves, eye protection, and hearing protection as needed
- Never open pressurized systems without proper venting
Preventive Maintenance to Avoid Recurrence
- Weekly: Visual checks for leaks, noise, and vibration
- Monthly: Lubrication, seal inspection, basic performance testing
- Quarterly: Shaft alignment, impeller inspection, filter cleaning
- Annually: Full overhaul of seals, bearings, and worn parts
- Keep detailed logs: flow rates, pressures, temperatures, vibrations, and maintenance actions
Pro tip: Predictive maintenance using vibration analysis and thermal imaging can prevent costly breakdowns.
Types of Centrifugal Pumps and Their Common Failure Modes
While centrifugal pumps come in many configurations—such as single-stage, multistage, self-priming, horizontal, and vertical—each type has distinct operational characteristics and common failure modes that can impact reliability if not properly managed.
Below is an overview of major centrifugal pump types and the most frequently encountered failure modes associated with each:
Single-Stage vs. Multi-Stage Centrifugal Pumps
Single-Stage Pumps
Typically used for high-flow, low-head applications (e.g., water supply).
Common Failure Modes:
- Impeller wear leading to reduced head and flow
- Bearing failure due to misalignment or poor lubrication
- Cavitation at high flow or low NPSHa
Multi-Stage Pumps
Designed for high-pressure applications like boiler feed or process water.
Common Failure Modes:
- Stage-to-stage leakage reducing overall efficiency
- Axial thrust imbalance causing excessive vibration
- Seal and gasket wear due to high differential pressure
🔧 Tip:Multi-stage pumps require stricter alignment and balancing during installation and maintenance.
End-Suction vs. Inline (Straight-Through) Pumps
End-Suction Pumps
Most common general-purpose design, with the suction entering from one end.
Common Failure Modes:
- Suction recirculation at partial loads causing vibration and noise
- Impeller or wear ring wear reducing efficiency
- Mechanical seal failure due to misalignment or thermal stress
Inline Pumps
Compact design where suction and discharge are aligned.
Common Failure Modes:
- Thermal expansion causing misalignment
- Higher sensitivity to pipe strain and vibration transfer
- Difficult access for maintenance compared to end-suction types
📌 Both types benefit from proper piping support and flexible couplings to minimize stress on the pump casing.
Self-Priming vs. Non-Self-Priming Pumps
Self-Priming Pumps(e.g., self-priming centrifugal pump, monoblock self-priming pump)
Designed to evacuate air and re-prime automatically.
Common Failure Modes:
- Airbound conditions due to poor priming chamber venting
- Check valve failure leading to repeated loss of prime
- Internal corrosion or fouling reducing self-priming capability over time
Non-Self-Priming Pumps
Require the suction line and casing to be fully primed before startup.
Common Failure Modes:
- Dry running due to loss of prime after shutdown
- Air ingestion through leaks in the suction line
- Difficulty achieving prime after maintenance or prolonged stoppage
💡 Self-priming designs are ideal for applications with intermittent flow or variable suction conditions.
Horizontal vs. Vertical Centrifugal Pumps
Horizontal Pumps
Easier to access for maintenance; suited for large flow applications.
Common Failure Modes:
- Foundation settling or misalignment causing vibration
- Bearing wear due to shaft deflection at high loads
- Shaft seal or packing leakage from misalignment or heat
Vertical Pumps
Space-saving; commonly used in deep wells or high-rise booster systems.
Common Failure Modes:
- Column pipe misalignment affecting rotor stability
- Stuffing box or mechanical seal issues due to poor lubrication
- Difficult priming due to air entrapment in the column
⚠️ Vertical installations demand precise alignment and often require special priming procedures.
Material-Specific Failure Modes
Stainless Steel Pumps
Used in corrosive or sanitary applications (e.g., food, pharmaceuticals).
Common Failure Modes:
- Stress corrosion cracking in high-chloride environments
- Pitting corrosion if passivation is not maintained
- Galling or seizing of stainless components under poor lubrication
Cast Iron Pumps
Common for general water applications.
Common Failure Modes:
- Rust and sediment buildup reducing hydraulic efficiency
- Brittle fracture in cold environments if not properly protected
- Weight-related installation and alignment challenges
Plastic (e.g., Polypropylene) Pumps
Lightweight and chemical-resistant.
Common Failure Modes:
- Thermal deformation at high temperatures
- UV degradation if exposed to sunlight over time
- Loss of structural rigidity leading to misalignment or seal failure
📘 Understanding the compatibility of pump materials with the pumped fluid and environment is critical to avoiding premature failure.
Engineering Insight:
Research in advanced materials, such as bio-based coatings and nanocomposites, is inspiring new approaches to reducing wear, corrosion, and failure in pumping equipment. Though not directly related to centrifugal pump hardware, studies in sustainable materials highlight the importance of selecting pump casings and components that resist environmental degradation.
Matching the Right Pump to the Job
Choose a pump based on:
- Required flow rateand head (pressure)
- NPSHavs NPSHr calculations
- Fluid properties (viscosity, temperature, corrosiveness)
- Space constraints and installation type (horizontal vs vertical)
- Need for self-priming capability
Energy Efficiency, VFDs, and System Curve Alignment
- Operate pumps near their Best Efficiency Point (BEP)
- Use Variable Frequency Drives (VFDs)to adjust speed based on demand
- Avoid operating to the far left of the BEP curve (risk of recirculation and vibration)
Align system resistance (valves, filters, piping) with the pump performance curve
When to Call an Expert and Cost Considerations
Seek professional support if you encounter:
- Persistent vibration or unusual noise
- Repeated seal or bearing failures
- Unexplained increases in power consumption
- Suspected internal damage such as impeller erosion or casing cracks
Cost Tip: In some cases, the price of replacing worn components (like bearings or seals) may approach or exceed the value of a new pump—evaluate repair vs replace carefully.
Frequently Asked Questions (FAQ)
What is the most common cause of centrifugal pump failure?
Cavitation, misalignment, bearing wear, seal failure, and loss of prime.
How often should I inspect my pump?
Weekly visual checks, monthly preventive maintenance, quarterly alignment, annual overhauls.
Can I run a centrifugal pump without priming?
Only if it’s a self-priming centrifugal pump or the system is already flooded.
What causes cavitation in centrifugal pumps?
Low suction pressure, high fluid temperature, or excessive suction lift reducing NPSHa below NPSHr.
How do I prevent loss of prime?
Use proper sealing, install check valves, ensure a stable liquid source above the pump.