What Is Eddy Current Testing for Chillers?

Eddy current testing (ECT) is a non-destructive test used on water-cooled chiller condenser and evaporator tubes to find wall loss, cracking, pitting, denting, and other flaws before they become leaks or efficiency killers. A probe with coils creates a changing magnetic field inside each tube; changes in impedance reveal metal loss, deposits, or flaws. The result is a fast, repeatable condition assessment without removing the tubes from service for long.

ECT is essential for facilities that rely on cooling for process loads, data centers, healthcare, and multifamily or large residential systems with hydronic chillers. It supports safer operation, higher capacity, lower energy use, and informed planning for repairs and replacements.

What Problems Can Eddy Current Testing Find?

• Pitting and general corrosion, including under-deposit corrosion
• Erosion from high water velocity and entrained solids
• Fatigue cracks near support plates and at the tubesheet
• Fretting and wear at baffles/supports
• Denting from deposits or mechanical damage
• De-alloying in copper alloys and localized thinning
• Blockage and fouling patterns that reduce heat transfer

ECT also helps grade tubes by severity so you can decide which to plug, sleeve, or continue to monitor.

When Should You Schedule ECT?

• Baseline at commissioning or after installing a used chiller
• Annually in harsh water conditions or once every 18–24 months in clean, well-treated systems
• After tube leaks, rapid approach-temperature increases, or abnormal vibration
• Before major shutdowns, renovations, or chiller overhauls
• After significant water treatment upsets, cooling tower contamination, or flood events

Many insurers, risk managers, and warranty policies expect NDT such as ECT to be performed by qualified specialists and documented, especially for large tonnage machines.

How the Process Works

1. Preparation and safety: isolate, lockout/tagout, drain, vent, and verify safe access.
2. Tube cleaning: mechanical brushing or chemical cleaning to remove scale and sludge so indications are readable.
3. Reference standard setup: calibrate on a certified standard matching tube alloy, OD, and wall.
4. Probe selection: correct probe diameter and frequency for the alloy and wall thickness.
5. Scanning: insert the probe and scan each tube at controlled speed; record impedance signals.
6. Analysis: interpret signals for wall loss, flaws, and deposit signatures; compare to baseline.
7. Reporting: tube-by-tube map with severity grading, photos/plots, and recommendations such as plugging, sleeving, or retesting intervals.

ECT is quick—hundreds of tubes per shift when preparation is done right—so downtime stays tight.

ECT vs. Other Methods

• IRIS ultrasonic: precise remaining-wall measurement; slower; great as a follow-up for critical indications.
• Remote field testing (RFT): for ferromagnetic tubes where standard ECT is not ideal.
• Videoscope/visual: useful to confirm deposits or mechanical damage.
• Hydro/pressure testing: leak checks but no early warning of thinning or pitting.

In practice, ECT is your fast screen; IRIS or visual is the targeted deep dive.

Why DIY Is Risky

ECT requires specialized probes, reference standards, and signal interpretation skills. Wrong probe sizing, poor cleaning, or skipping calibration can miss dangerous defects or cause false calls. Over-aggressive cleaning can thin tubes. In addition, many insurance and compliance programs require documentation from qualified personnel. Attempted DIY can void warranties, increase liability, and extend downtime.

What Drives Cost and Duration?

• Number of tubes, tube length, and accessibility
• Alloy and diameter (affects probe selection and scan speed)
• Level and type of fouling (pre-cleaning needed)
• Availability of accurate reference standards and historical data
• Reporting detail (basic grading vs. lifecycle plan)

Strategic planning—doing ECT in shoulder seasons—keeps cooling available during peak heat.

Cleaning and Preparation Tips

• Use the least aggressive effective method to avoid wall loss on thin tubes.
• Rinse thoroughly after chemical cleaning; neutralize to protect against flash corrosion.
• Verify brush size and condition; worn brushes leave deposit shadows that mimic defects.
• Document water chemistry and tower conditions to correlate with findings.

Common Mistakes to Avoid

• Skipping cleaning or mixing data from dirty and clean tubes
• Using incorrect probe frequency for the alloy
• Scanning too fast and missing near-support indications
• Ignoring the evaporator bundle while focusing only on the condenser
• Not retesting after plugging or sleeving to establish a new baseline

Interpreting Results and Taking Action

Good reports rank tubes by percent wall loss and note indication types and positions (inches from tubesheet, near support, free span). Typical actions include:

• Monitor: recheck in 6–18 months for mild thinning
• Plug: isolate tubes with severe defects or leaks
• Sleeve or replace: extend life when the pattern is localized
• Root-cause: address water treatment, flow velocity, or debris screens to stop repeat damage

Southern California Considerations

Coastal air can add chlorides; inland dust and wildfire ash increase tower solids. Extended cooling seasons and part-load operation can hide early efficiency loss. Scheduling ECT in spring or fall helps balance uptime with maintenance windows. Facilities across Los Angeles County and nearby areas—including Orange County, Ventura County, and Western Riverside County—see the best outcomes when ECT is paired with consistent tower maintenance and water treatment.

Cities we commonly serve include Los Angeles, Long Beach, Santa Monica, Pasadena, Glendale, Burbank, Anaheim, Irvine, Santa Ana, Newport Beach, Costa Mesa, Fullerton, Huntington Beach, Ventura, Oxnard, Thousand Oaks, Riverside, Corona, and Temecula.

Who We Are

#1 AC Guys is a family HVAC business in Southern California. Our family of engineers is in its 4th generation, with 80+ years of engineering experience. We specialize in commercial and residential systems, taking on large and complex projects with a focus on indoor air health. Our engineers have factory training at Fujitsu (Japan), Mitsubishi Elektrik (Thailand), Midea (China), Gree (China), and Hier (China). We operate across Los Angeles County and nearby areas including Orange County, Ventura County, and Western Riverside County.

Our mission is simple: healthy air at home and at work supports a healthy life. With disciplined testing like chiller eddy current inspections, you can manage risk, protect warranties and insurance requirements, and keep cooling performance on track.