Every Coil is Leak Tested Twice to Assure Quality

At Marlo Heat Transfer Solutions, quality isn’t just a goal or a philosophy. It’s our constant focus throughout the development of every heating and cooling coil we manufacture. That includes the design and engineering phase, the entire production process, and the topic of this story – the thorough leak testing we perform on every coil, which assures reliable performance.

We understand that our customers rely on our commercial and industrial coils to perform in a wide range of applications, often under demanding conditions. That’s why we take every step necessary to ensure that each coil we manufacture meets the highest standards of durability and reliability.

One of the most critical aspects of our quality control process is our extensive leak testing. Every single coil – from chilled and hot water coils, to steam coils, to industrial process coils and everything in between – goes through two distinct leak tests, both during and after production. This ensures that every coil we produce is free from defects and built to last.

Leak Test #1: During Tube Expansion

The first test of every Marlo heating coil and cooling coil occurs before production is even completed. After the tubes are laced through the fins and casing, they are expanded to create a strong mechanical bond to the fins, which also allows maximum heat transfer.

The tube expansion is created using very high hydrostatic pressure – typically more than 2,000 psi – which would cause any faulty hairpin bends or brazed joints to immediately fail. All tubing and connections that survive this level of pressure are obviously strong enough to withstand whatever working pressure at which the coil will operate in its application.

Leak Test #2: Submersion Testing for Micro-Leak Detection

Once a Marlo coil is completed and ready to ship to our customer, it goes through one final leak test to assure it is ready for field use. This is a very time-consuming process, but virtually guarantees we will identify even the smallest leak.

First, we fully pressurize the completed coil to 1.5 times its intended working pressure, then fully submerge it under water in one of our large test tanks. While the coil is submerged, members of our quality control team monitor the pressure gauges attached to the coil for any drop in pressure which would indicate a leak.

At the same time, experienced Marlo employees carefully watch for any sign of tiny air bubbles, which would identify a micro-leak that might not even be detected by the pressure gauges. The coil remains underwater for several minutes, allowing the inspectors to check for leaks on all sides and from multiple angles to be certain there are no signs of leaks. Only after passing this stringent test is the coil allowed to be shipped to our customer.

By implementing these rigorous testing procedures, we ensure that every coil we manufacture is leak-free and ready to offer maximum performance and long-term reliability. When you choose Marlo heating and cooling coils, you can rest assured that you’re getting a high-quality product every single time.

With Testing This Good, It’s No Wonder We Offer the Industry’s Best Warranty

Our extensive leak testing (along with our quality materials and manufacturing processes) gives us the confidence to back every heating and cooling coil we make with a 3-year warranty. In an industry where most coil manufacturers offer no more than a 12-month warranty, we’re proud to back our products for three times longer than our competitors! We feel this is one of many reasons why Marlo coils offer the best value in the industry.

Ready for a Coil That Delivers Unmatched Reliability?

When you want a well-made, thoroughly tested commercial or industrial heating or cooling coil, we would be honored to build one for you. Just contact your local Marlo Independent Manufacturer’s Representative (IMR) to discuss your needs. You can find your rep by entering your zip code in our IMR Locator.