Why does your Burgmann mechanical seal keep failing? 9 common causes and fixes

A mechanical seal rarely fails without warning.

In most industrial pumps, seal failures develop gradually as a result of dry running, shaft misalignment, vibration, contamination, unsuitable seal materials, or operating conditions that exceed the seal's design limits. What begins as a minor leak or slight increase in vibration can quickly become an expensive shutdown if the underlying cause is ignored.

Replacing a failed Burgmann mechanical seal without understanding why it failed often leads to the same problem occurring again. Identifying the root cause before installing a replacement seal helps improve equipment reliability, reduce maintenance costs, and extend the service life of both the seal and the pump.

Whether you're maintaining process pumps in chemical plants, water treatment facilities, oil and gas operations, food processing, or other industrial applications, understanding why mechanical seals fail is essential for preventing repeated downtime.

This guide explains the nine most common causes of Burgmann mechanical seal failures, the warning signs to look for, and practical solutions to improve seal performance and pump reliability.

Key takeaways

Operating conditions rather than manufacturing defects usually cause repeated mechanical seal failures. Dry running, shaft misalignment, excessive vibration, contaminated process fluids, incorrect seal material selection, cavitation, thermal shock, and poor installation are among the most common reasons seals fail prematurely.

Identifying and correcting these issues helps improve seal life, reduce downtime, and lower maintenance costs.

Why mechanical seals fail

A mechanical seal is designed to create a reliable sealing interface between rotating and stationary components while preventing process fluid from escaping the pump.

For the seal to operate correctly, the seal faces must remain properly aligned, adequately lubricated, and compatible with the operating pressure, temperature, and process fluid. When any of these conditions change, friction increases, heat builds up, and seal faces begin to wear much faster than intended.

Many seal failures that appear sudden are actually the result of operating problems that have developed over time. Understanding these underlying causes allows maintenance teams to fix the real problem instead of repeatedly replacing seals.

Some of the most common reasons mechanical seals fail include:

• Dry running
• Incorrect installation
• Shaft misalignment
• Excessive vibration
• Contaminated process fluid
• Incorrect seal material selection
• Cavitation
• Thermal shock
• Operating beyond design limits

Understanding these failure mechanisms is the first step toward improving pump reliability and extending mechanical seal life.

Dry running

Dry running is one of the most common and destructive causes of mechanical seal failure.

Mechanical seals rely on a thin film of process fluid between the seal faces for lubrication and cooling. When this fluid film disappears, friction increases almost instantly, generating excessive heat that damages the seal faces within a very short period.

Even a brief period of dry running can permanently damage seal components and lead to immediate leakage after startup.

Common warning signs

• Burn marks on the seal faces
• Cracked carbon rings
• Blue discoloration caused by overheating
• Leakage immediately after startup

How to prevent failure

• Prime the pump before startup.
• Ensure a continuous supply of process fluid.
• Install dry-run protection where appropriate.
• Monitor operating conditions during startup and shutdown.

Incorrect installation

Even the highest-quality mechanical seal can fail prematurely if it is not installed correctly.

Mechanical seals are precision-engineered components that operate within very small tolerances. Contaminating the seal faces, damaging elastomers during assembly, applying uneven bolt torque, or incorrectly compressing the seal can all reduce sealing performance before the pump even starts operating.

Defective seals do not cause many leaks that occur immediately after installation. They result from installation practices that prevent the seal from operating as intended.

Taking the time to follow the correct installation procedure helps maximise seal life and reduces the likelihood of repeat failures.

Common warning signs

• Leakage immediately after installation
• Uneven wear on the seal faces
• Excessive vibration
• Short seal service life

How to prevent failure

• Follow the manufacturer's installation instructions.
• Clean all sealing surfaces before assembly.
• Use the correct installation tools.
• Verify shaft dimensions and gland alignment before startup.
• Avoid touching or contaminating the seal faces during installation.

Shaft misalignment

Mechanical seals are designed to operate with minimal shaft movement.

When the pump shaft and motor are not properly aligned, uneven forces are applied to the seal faces throughout operation. This creates excessive wear, increases heat generation, and gradually damages both the seal faces and supporting components.

In many cases, repeated seal failures are actually symptoms of alignment issues elsewhere in the pumping system.

Correcting shaft alignment not only extends seal life but also improves bearing life, reduces vibration, and enhances overall pump reliability.

Common causes

• Improper motor alignment
• Bent pump shafts
• Worn bearings
• Foundation movement
• Installation errors

How to prevent failure

• Perform laser shaft alignment during installation.
• Check alignment during scheduled maintenance.
• Measure shaft runout using a dial indicator.
• Replace worn bearings before they affect alignment.
• Inspect shaft sleeves for wear that could affect sealing performance.

Excessive pump vibration

Excessive vibration places continuous stress on every rotating component inside the pump, including the mechanical seal.

As vibration increases, the seal faces struggle to maintain stable contact, causing uneven wear, leakage, and premature failure. Over time, vibration can also damage O-rings, loosen hardware, and shorten the life of bearings and shafts.

Because vibration is often a symptom of another mechanical or hydraulic problem, identifying its source is just as important as replacing the failed seal.

Common warning signs

• Chipped or damaged seal faces
• Damaged O-rings
• Loose gland hardware
• Frequent seal leakage
• Increased operating noise

How to prevent failure

• Monitor vibration using condition monitoring systems.
• Balance rotating equipment regularly.
• Replace worn bearings promptly.
• Maintain proper shaft alignment.
• Investigate abnormal vibration before replacing the seal.

Contaminated process fluid

Mechanical seals depend on clean process fluid to maintain a stable lubricating film between the seal faces.

When abrasive particles, crystallised product, or other contaminants enter the sealing interface, they scratch the seal faces and accelerate wear. Over time, even small amounts of contamination can significantly reduce seal life and increase the risk of leakage.

Applications involving slurries, suspended solids, or crystallising fluids require particular attention to fluid cleanliness and seal design.

Industries where contamination commonly affects seal performance include:

• Mining
• Chemical processing
• Wastewater treatment
• Pulp and paper manufacturing

How to prevent failure

• Install effective filtration systems where appropriate.
• Use seal flush plans for demanding applications.
• Select wear-resistant seal face materials for abrasive services.
• Monitor process fluid quality during operation.

Common mechanical seal failure symptoms

Incorrect seal material selection

A mechanical seal may be installed correctly and operate within the recommended pressure and temperature limits, yet still fail prematurely if the seal materials are not compatible with the application.

Seal faces, elastomers, and secondary sealing components must be selected based on the process fluid, operating temperature, pressure, and the presence of abrasive particles. An incorrect material can swell, corrode, crack, or wear much faster than expected, leading to leakage and repeated seal replacement.

Choosing the right material is one of the most effective ways to improve seal reliability and extend service life.

Always evaluate chemical compatibility, operating temperature, pressure, and process conditions before selecting a replacement mechanical seal.

Cavitation

Cavitation is one of the most damaging hydraulic problems affecting pumps and mechanical seals.

It occurs when the pressure inside the pump drops below the liquid's vapour pressure, causing vapour bubbles to form. As these bubbles move into higher-pressure areas, they collapse violently, generating shock waves that damage the impeller and transmit vibration throughout the pump.

Although cavitation primarily affects hydraulic components, the resulting vibration and instability significantly reduce mechanical seal life.

Common warning signs

• Loud rattling or crackling noise
• Pitting on the impeller surface
• Increased vibration
• Reduced pump performance
• Repeated mechanical seal failures

How to prevent failure

• Ensure adequate Net Positive Suction Head (NPSH).
• Eliminate restrictions in the suction line.
• Operate the pump close to its Best Efficiency Point (BEP).
• Monitor suction conditions during operation.

Thermal shock

Mechanical seal faces are designed to operate within a controlled temperature range.

When they experience sudden temperature changes, the seal faces expand or contract at different rates. This uneven thermal movement creates internal stresses that can crack brittle seal materials and permanently damage the sealing surfaces.

Thermal shock is particularly common during rapid startup, sudden cooling, or large process temperature fluctuations.

Common causes

• Sudden cold-water flushing
• Steam cleaning
• Rapid startup after shutdown
• Large temperature fluctuations during operation

How to prevent failure

• Allow equipment to reach operating temperature gradually.
• Avoid sudden temperature changes whenever possible.
• Select seal materials suitable for the operating temperature.
• Follow recommended startup and shutdown procedures.

Operating beyond design limits

Every mechanical seal is designed to operate within specific pressure, temperature, shaft speed, and fluid compatibility limits.

Running equipment outside these limits increases friction, heat generation, and mechanical stress, all of which shorten seal life. Even a high-quality mechanical seal will fail prematurely if it is continuously exposed to operating conditions beyond its design capabilities.

Before selecting or replacing a mechanical seal, always verify that it is suitable for the actual operating environment.

Confirm the following:

• Maximum operating pressure
• Operating temperature
• Shaft speed
• Process fluid compatibility
• Pump operating conditions

Selecting a mechanical seal that matches your application's requirements is essential for achieving reliable, long-term performance.

Mechanical seal failure troubleshooting

Preventing future mechanical seal failures

Most mechanical seal failures can be prevented through regular inspections and good operating practices. A proactive maintenance program helps identify wear before it leads to leakage, equipment damage, or unexpected downtime.

Good maintenance practices include:

• Inspect shaft alignment during scheduled maintenance.
• Monitor vibration and bearing condition.
• Keep process fluids clean.
• Select seal materials suitable for the application.
• Follow recommended installation procedures.
• Replace worn shaft sleeves and bearings promptly.
• Avoid prolonged dry running.

Condition monitoring tools such as vibration analysis and thermal imaging can also help detect developing problems before they result in seal failure.

Frequently asked questions

How long should a Burgmann mechanical seal last?

Seal life depends on operating conditions, installation quality, maintenance practices, and material selection. When properly installed and operated within its design limits, a mechanical seal can provide years of reliable service.

Can a leaking mechanical seal be repaired?

Minor installation issues may sometimes be corrected, but worn seal faces, damaged elastomers, or cracked components generally require seal replacement.

What is the most common cause of mechanical seal failure?

Dry running is one of the most common causes, followed by incorrect installation, shaft misalignment, contamination, and excessive vibration.

Which seal material is best for abrasive applications?

Silicon carbide and tungsten carbide are both widely used for abrasive applications. The most suitable material depends on the operating conditions, pressure, and type of process fluid.

Stop replacing seals. Start fixing the real problem.

Repeated mechanical seal failures are usually symptoms of an underlying issue rather than a faulty seal. Identifying problems such as dry running, misalignment, contamination, cavitation, or incorrect material selection helps improve seal life, reduce downtime, and lower maintenance costs.

Replacing the seal without correcting the root cause often results in the same failure occurring again.

Need help replacing your Burgmann mechanical seal?

Choosing the right replacement seal involves more than matching dimensions. It also requires selecting the correct materials and seal design for your operating conditions.

Trisun manufactures OEM-compatible mechanical seals designed to replace Burgmann mechanical seals across a wide range of industrial applications. Our engineering team can help you identify the cause of repeated seal failures and recommend the most suitable replacement for long-term, reliable performance.

Contact Trisun today to find the right Burgmann-compatible mechanical seal for your application.