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Refrigerant Leak Detection Methods

In Articles by Elizabeth OrtliebLeave a Comment

Effective refrigerant leak detection is vital for ensuring safety and achieving compliance as well as maximizing energy efficiency and minimizing operation costs. There are several refrigerant leak detection methods that residential technicians can use to find a refrigerant leak, and you need to employ the best ones, along with the right instrumentation, to accurately find and fix refrigerant leaks.

How to Find a Refrigerant Leak

As an HVAC professional, you have a business responsibility to find and fix refrigerant leaks through preventative and corrective maintenance. In addition, various regulatory jurisdictions at the local, state, and federal levels (e.g., EPA 608) require regular leak inspections.

These requirements to find refrigerant leaks can be successfully met by employing the best refrigerant leak detection method(s) for your job needs. Refrigerant leak detection methods include, but are not limited to:

  • soap bubble method;
  • fluorescent dye method; or
  • electronic leak detection method.

As you can see, there are numerous methods that you can use; each with their own benefits, and this is where you need to pay close attention. That’s why we are going to start by looking at the more traditional methods and then move to the newer methods. By the end, you will find out which methods are best.

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Soap Bubble Method

The soap bubble method is a mainstay that has been relied upon by residential technicians for decades. It’s fairly self-explanatory. In essence, you apply soapy water or a leak detection spray to see if there are leaks at certain points. Bubbles should appear at leakage points.

While common and trusted, what undermines the soap bubbles method is the fact that it can be difficult to pinpoint leaks under certain conditions, such as if the leak is very small or if it is windy outdoors. That’s why it may be most beneficial for you to use the soap bubble method in combination with another method, particularly with one of the electronic leak detection methods.

Ultraviolet / Fluorescent Dye Method

This method uses a specialized dye that is injected into the refrigeration system and circulated along with the host fluid or refrigerant. If there are any leak points in the system, the dye will escape and concentrate at these locations. Using a UV lamp, these leak points can be easily seen and identified.

It should be noted that there is a major downside with this method: that is, the fluorescent dye method can adversely affect the performance and long-term operation of your HVAC-R system(s).

Electronic Refrigerant Leak Detection Methods

These are the most precise and efficient refrigerant leak detection methods. Leak technologies in this category include corona-suppression (negative corona), heated diode, infrared (IR), and ultrasonic. We are now going to provide more detail about these various electronic leak detection technologies.

Corona-suppression (Negative Corona)

This is a traditional electronic leak detection technology, in which two electrodes inside an instrument have a current passing between them. This current has a known baseline. As a result, when a refrigerant gas enters the instrument and passes through these electrodes, there is an interference in the current and thus a drop in current. This drop in current indicates to the instrument that there is a gas present, and the alarm sounds. The more interference, and thus current drop, the higher the concentration of the refrigerant gas.

One thing to consider is that this technology is prone to false-positives, which leads us to our next point:

Heated Diode

Heated diode leak detection involves heating a refrigerant to the point that the molecules are broken apart. This reaction results in the presence of positively charged concentrations of chlorine or fluorine, chemical elements which are found in the majority of refrigerants on the market today.

The heated diode technology used in electronic refrigerant detectors, such as the Bacharach H-10 PRO, will detect the chlorine or fluorine ions and trigger an audible alarm to identify a leak. Indeed, this technology is less likely to give false alarms compared to corona-suppression.


Infrared leak detection is a technology in which infrared light is applied to detect refrigerant. The refrigerant absorbs some of the infrared light, and the degree of change in refrigerant concentration is measured.

This is a sensitive and accurate technology, and one such example is the Bacharach Tru Pointe IR, which utilizes a long-life infrared sensor in a low-cost package to effectively pinpoint refrigerant leaks.


This technology detects the noise refrigerants and other gases make when they are leaking. As a refrigerant leaks from an HVAC-R unit, it makes an ultrasonic noise that can’t be heard by the human ear. An ultrasonic detector, such as Bacharach’s True Pointe Ultra, True Pointe 1100, or True Pointe 2100, reacts to that noise and pressure.

After going over the numerous refrigerant leak detection methods available, you can see that none of them are the same, which leads us to our next point: You need to choose the method(s) that are best for you to find a refrigerant leak.

Chart comparing the effectiveness of common refrigerant leak detection methods used by HVAC technicians.

Best Way to Find a Refrigerant Leak

Indeed, the most popular refrigerant leak detection methods for HVAC-R technicians today are the electronic refrigerant leak detection methods, particularly the heated diode and infrared technology.

Now, the most appropriate refrigerant leak detection method(s) are based on your application and individual needs. While some technicians may express great confidence in the use of older methods, you need to realize that electronic leak detection methods are the most efficient; They detect a wide range of refrigerants faster, plus they are safer and more efficient.

Of course, there is no one-size fits all solution, and the method(s) that are right for you depend on your specific application. Ultimately, it’s important that you have the right instrumentation to perform your refrigerant leak detection.

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Which combination of refrigerant leak detection methods do you use to locate refrigerant leaks? Let’s continue the conversation in the comments below.

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