Conducting Leak Testing on Refrigerant Tube Assembly & Final Assembly

In the refrigerant industry, it’s very important to have a reliable, repeatable leak test, as leaks can have hazardous and dangerous ramifications.

Refrigerant tube assembly and final assembly leak testing is an important step in the manufacturing process as it is usually the last chance to check for leaks before a product is shipped. There are procedures to follow both pre- and post- refrigerant fill to ensure product quality.

Pre-Testing Prior to Refrigerant Fill

Prior to refrigerant fill on final assemblies and tube assemblies, pre-test procedures are conducted, following these steps:

1. Perform a gross leak test using Pressure Decay technology (usually you’ll skip this test if a proof test was already conducted)

2. Then you’ll do a Vacuum Decay test to evacuate the part to a certain vacuum level prior to tracer gas fill

3. Fill the part with either helium or forming gas* to perform a trace gas test using one of the below methods:

• Sniff Leak Test
• Nitrogen Purge Leak Test
• Hard Vacuum Mass Spec Leak Test (Helium only)
• Exhaust the trace gas out of building or reclaim helium to save money

4. Additionally, often you’ll do a High Vacuum Pump Out which verifies there is no moisture in the system prior to refrigerant or a nitrogen charge is added to the assembly prior to shipping

*Note: Helium supply has been known to become scarce and/or quite expensive. Forming gas is a popular alternative. Forming gas is a mixture of hydrogen and nitrogen, typically in a ratio of 5% H2 to 95% N. At this concentration, manufacturers don’t need to worry about the flammability of hydrogen, but it does require some considerations for an accurate test. Learn more >

Post-Testing After Refrigerant Fill

General methods used for leak testing after refrigerant fill to ensure product quality are:

• Leak Location using sniff technology to check for A2L leaking potential from certain locations
• Nitrogen Purge technology using a clam shell device to check specific joints for very small leak rates. This technology lends itself well to robotic, automated motion**
• Hard Vacuum Mass Spec Testing technology using an RGA detector tuned to measure molecular flow of A2L leaking from the part

**Note: These types of applications lend themselves well to automation. With the help of Inficon, CTS uses robotic sniff and sensing technology that can integrate a nitrogen purging clamshell into a sniffing area that’s automated with a robotic arm. This allows you to get closer to the area where the parts are leaking and automate your test for greater efficiency.

CTS Has Your Solution for Reliable, Cost-Effective Refrigerant Leak Testing

At CTS, we have a full range of proven leak test solutions using a variety of test methods available to support manufacturers of residential and commercial HVAC and refrigerant products throughout the assembly process. Our HVAC/R testing equipment can be used for a broad spectrum of test configurations for many different products.

CTS can help you build and design effective leak test systems for a wide range of components, including compressors, evaporators, condensers, coils, valves, heat exchangers, tubing (long and short variations), pressure switches, and more.

Contact the leak test experts at CTS can assist you in identifying the best solution for your manufacturing leak test application.