Refrigerant Leak Detection: Where 'Best' is a Relative Term

By this time on your career path as an HVACR technician and/or field-active business owner, you should already be aware of the methods used to find refrigerant leaks. Your choice of tool — whether a straightforward visual inspection, soap bubbles, electronic sensors, ultrasonic detectors, refrigerant dyes, a combination of two, three, or all of them — is totally up to you.

The question I’m often asked is “Which one is the best?” My answer is that there’s no “best” method. This isn’t about being absolute, comparing one to other, or using one method only because it’s the latest and greatest method. The question should be, “Which tool or tools would be the most effective in my particular situation?”

Special Soap Formulas Aid Visual Detection
First, use your eyes. If you can gain access to piping and components to look for obvious oil stains, then do it. Oil residue can indicate where a system may have leaked or is currently leaking. In the same scenario, another visual detection method is to use soap bubbles. This is an extremely effective method for detecting continuous leakage. However, keep in mind that it helps to use the more complex specialty formulations, which offer high sensitivity bubble development instead of dish soap. But if regular soap is all you have, don’t hesitate to use it.

Electronic Detectors: Precise in Ideal Conditions
Electronic detectors are precise instruments, as long as your sensors are replaced at their recommended usage period and the wind isn’t blowing around a system that is located outdoors. One of the many observations that I’ve made from the past 13 years of studying refrigerant leak — along with their manifestations, and numerous exit paths — is that it’s easy to understand why it could turn into an extremely frustrating task.

I’ve found that the best way to improve efficiency when using sniffers is to visualize a plane of leakage anywhere along the radius of a semispherical dome. Move your electronic sensor in a pattern which would reflect this half ball model by using a circling motion, covering the points of radius as you move along the pipe surface. This allows you to detect those leaks which are not exiting in what we like to imagine as a 45 degree vertical plane from the pipe’s horizontal surface.

Ultrasonic detectors are ideal for targeting leak sites because they aren’t affected by air currents. But remember, settings lose their edge when used in commercial and industrial settings. This is because of the multitude of other frequencies being generated by compressed air, and steam movement through pipes in addition to leakage.

Ultraviolet Dyes: Use in Moderation Ultraviolet dyes are excellent for targeting intermittent leakage, just don’t overdose the system because you’re in a hurry to find the leak. Putting ultraviolet dyes into the system as an early detection method avoids this situation. Too much dye will affect performance output of a unit and cause a mess when you attach or disconnect manifold gage sets and auxiliary equipment. Remember that most dyes will react to internal moisture. They’ll crystallize, and lose their ability to be carried by the refrigerant and oil. Look for UV dyes which offer moisture resistance capabilities, fast acting injection, and a low product volume to system oil ratio.Leak Type Dictates Method So, which leak detection method is the best for a particular application? Let’s first define the two types of leaks: intermittent and continuous. Intermittent leakage is due to free flowing internal particulates, operation vibrations, varying temperature swings and load change conditions. Continual leakage is always a factor, because everything leaks, over the course of one year or 20 years. Being that people are far from perfect, it comes as no surprise that we can’t design and build a perfectly tight system. Entropy is always at work. But don’t let that stop you. Continue to search for refrigerant leaks as you would for buried treasure, and use these methods in the same way that our country’s military combines the Air Force, Navy, Army, and Marines to get the job done. A variety of leak detection methods can be employed as needed, if you’re seeking to be a competitive, efficient, and economical business manager or technician, all the while keeping your business growing, and your customers happy.