Leaks in shell & tube heat exchangers can lead to contamination, reduced thermal performance, and costly downtime if not addressed quickly. While some leaks are obvious, many begin as small, difficult-to-detect issues that gradually worsen. Understanding where leaks occur and how to diagnose them helps operators take action before a repair or replacement becomes urgent.
This guide covers the most common leak sources, how to identify them, and what steps to take once a leak is discovered.
Why Heat Exchanger Leaks Happen
Leaks often begin as microscopic cracks, weakened seals, or tube wall thinning. Over time, operating cycles, fouling, and corrosion accelerate the breakdown of components. By the time contamination becomes noticeable, the problem may already be advanced.
If your system is showing efficiency loss or strange pressure behavior, first review
5 Early Warning Signs Your Heat Exchanger Needs Maintenance.
Common Leak Points in Shell & Tube Heat Exchangers
Several components are especially prone to leakage. The most frequent problem areas include:
- Tubes – Cracking, pitting, erosion, or corrosion can cause perforations.
- Tube-to-tube-sheet joints – Leaks occur when joints loosen, crack, or fail from stress or corrosion.
- Gaskets and flanges – Aging or improperly tightened gaskets allow seepage.
- Shell-side welds or seams – Fatigue or corrosion can compromise structural integrity.
- Channel covers or heads – Improper seating or damaged sealing surfaces cause leakage.
If your inspection reveals corrosion contributing to the leak, see
How to Prevent Corrosion in Heat Exchangers.
Signs That a Leak Is Developing
Even small leaks produce noticeable symptoms. Operators should watch for:
- Unexpected changes in fluid purity or contamination
- Loss of heat transfer performance
- Rising pressure drop across the unit
- Moisture or residue near gasketed areas
- Foaming, discoloration, or inconsistent fluid flow
For broader inspection strategies, review
Routine Inspections for Shell & Tube Heat Exchangers.
How to Troubleshoot a Suspected Leak
Once you suspect a leak, a structured diagnostic approach helps pinpoint the exact source. Consider the following steps:
- Check for cross-contamination – Lab testing the two fluids often reveals internal leakage.
- Inspect the bundle visually – Look for pitting, cracks, or thinning on tube surfaces.
- Perform a pressure test – Pressurizing one side of the exchanger helps identify failing tube joints or perforations.
- Dye penetrant or helium testing – Useful for detecting microscopic cracks or pinhole leaks.
- Monitor pressure and temperature trends – Sudden changes may indicate the location or severity of a leak.
If fouling is involved, cleaning may reveal the root cause. See
Mechanical vs. Chemical Cleaning for Heat Exchangers.
When a Tube Bundle Needs Replacement
If multiple tubes are compromised or if corrosion is widespread, repairing individual tubes may not be enough. Leaks caused by thinning, stress cracking, or repeated failures often indicate it’s time for a replacement bundle.
KAM Thermal Equipment manufactures:
- Custom replacement tube bundles
- Drop-in replicas of discontinued or OEM units
- Upgraded designs using corrosion-resistant materials
For a full breakdown of the process, read
our tube bundle removal & replacement guide.
How to Prevent Future Leaks
Most leaks are preventable through thoughtful maintenance and monitoring. Reducing stress, controlling fouling, and selecting proper materials all play a major role in longevity.
Key prevention strategies include:
- Monitoring temperature and pressure regularly
- Maintaining water quality and fluid chemistry
- Selecting corrosion-resistant materials during replacement
- Removing fouling before under-deposit corrosion forms
- Avoiding rapid thermal cycling and water hammer
Learn more about thermal stress reduction in
Preventing Thermal Shock in Heat Exchangers.
Additional Resources
- Preventative Maintenance Strategies
- Straight Tube vs. U-Tube Cleaning Guidance
- Benefits of Custom Shell & Tube Manufacturing
Service Areas
KAM Thermal Equipment supports industrial operators across the United States with custom fabrication and engineered replacement solutions. Explore service coverage by region:
Mid-Atlantic
Southeast
Midwest
South Central
Need a Replacement Tube Bundle?
KAM Thermal Equipment provides custom replacement tube bundles and complete shell & tube solutions engineered for long-term performance. If troubleshooting reveals tube failure or wear, our team can produce an exact-fit, application-specific replacement.