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The Benefits of Using an Ultrasonic Leak Detector to Find Refrigerant Leaks!

Updated: Nov 20, 2023

A refrigerant leak may be easy to find when the leak is a large one but when the leak is small, finding it can be tedious and time consuming unless the right leak detection tool is used. If a leak exists in a system, the leak may be anywhere such as in the condenser, evaporator coil, line set, or a fitting, component, or joint. Searching all of these areas must be done quickly and with confidence. Regardless of the type of gas within the HVACR system, an ultrasonic leak detector can narrow down the leak location fairly consistently and with the least amount of passes across the tubing sections.

While an ultrasonic leak detector is not going to make that closet that you are working in any bigger, it will significantly reduce the amount of time that you may otherwise waste trying to guess about a leak's location. At the same time, it can help provide an ease of mind that you are not wasting your time using a leak detection method that is inaccurate or time consuming.

For the sake of covering this topic, I will be utilizing the Accutrak VPE-GN Pro which you can pick up on or here! I will briefly go over how this tool functions before explaining the benefits.

An ultrasonic leak detector works by picking up ultrasonic noise and translating it into an audible sound that can be heard by the human ear. For that reason, this tool is not disrupted by ordinary sound such as background noise or wind. Additionally, the specific sound profile of an ultrasonic “leak” will be different than the ultrasonic noise that may be put off by other equipment (i.e. compressors, motors, fluorescent lighting, etc.). However, these tools work best when the HVACR system is off.

When it comes to searching for a leak, an ultrasonic leak detector works best right after shutting off the compressor. Remember that the compressor circulates both refrigerant and refrigerant oil through the tubing. If the compressor just shut off, there should be oil covering all the inner walls of the tubing. When a leak spot exists in the tubing, the pressurized gas must pass through the oil before exiting the tubing through the leak. This produces a loud squealing noise that is ultrasonic. This makes a louder ultrasonic noise for the detector to pick up. Another way to create this effect is to wet down the coils of the system with water. In air conditioning mode, the evaporator coil is already wet due to condensation on the coil. An outdoor condensing unit can be wet down using a hose or spray bottle to produce the loudest ultrasonic noise.

Below, are 10 benefits of using ultrasonic leak detection to find refrigerant leaks!

Benefit #1: Ultrasonic Leak Detectors Can be used when it is windy outside.

Although heavy winds can interfere with other leak detection methods like refrigerant sniffers (heat diode), there is little effect from the wind when using an ultrasonic leak detector. It all comes down to frequency. Wind makes noise but it is usually not ultrasonic. The noise of a refrigerant leak can be picked up by the tool because first of all, it is ultrasonic noise and secondly, it is a unique noise.

Benefit #2: Ultrasonic Leak Detectors Can be used immediately with no wait or warm-up time.

Unlike other leak detection methods that require a longer start up process or methods such as dyes that require a return visit, an ultrasonic leak detector can be used as soon as it is turned on.

Benefit #3: They Can be passed by the tubing quickly and still pick up leaks.

Ultrasonic leak detectors work at the speed of sound meaning there is no need to move the tool tediously and slowly across an area to search. Instead, a thorough and accurate check can be done while moving at a reasonable speed. As soon as the device is aimed toward the leak from a proper range, a change in the audio and display will occur.

Benefit #4: They Do not need to be calibrated for a specific refrigerant

Regardless of whether you are testing for a leak in a system using HFC (R-410A), HCFC

(R-22), or another refrigerant type, the tool does not need to be calibrated for the specific refrigerant that it is detecting.

Benefit #5: No need to replace or change the tip

There is no degradation in the tool's sensing ability like other tools that need the tip changed over time or use. It doesn’t matter what application the leak detector is being used for or how large or small the leak is. The tip of this tool is only a tube that noise travels through.

Benefit #6: No Special Batteries or Chargers are needed

While some leak detectors may require special batteries or chargers, an ultrasonic leak detector, such as the Accutrak VPE-GN Pro only requires a 9-volt battery.

Benefit #7: This detector Signals at the Leak Point

Unlike other forms of leak detection, such as heated diode or infrared detectors, the ultrasonic leak detector immediately signals the presence of a leak once it is encountered. Infrared detectors rely on a change in light to indicate a leak, meaning you cannot stop moving the tool. The tool must be moved back and forth across the supposed leak location. A heated diode, requires a delay until the chemical can be pumped across the sensor. Because of this, the tool may not react until you are past the leak location. An ultrasonic detector, will immediately detect the leak at the speed of sound.

Benefit #8: One Ultrasonic Leak Detector Will Work for All Refrigerants

You will only need to purchase one ultrasonic leak detector no matter how many different refrigerants or refrigerant types you are working with.

Benefit #9: They require No field Calibration

With ultrasonic leak detectors, there is no start up time and no need for calibration. As soon as the device is powered on, it is ready to work.

Benefit #10: They Will Work for Any Type of Pressurization

Because this tool does not rely on a specific calibration for different refrigerants, or a sensor that is only good for one type of refrigerant chemical. This means that the ultrasonic leak detector can be used to find a leak in any pressurized line. This comes in handy when the system is pressurized with nitrogen. Remember, ultrasonic leak detectors work best when there is oil inside the tubing with the pressurized gas. This makes the tool a great selection for finding refrigerant leaks in HVACR systems.

Are you looking for more info about leak detection and ultrasonic leak detectors? Be sure to check out our "Advantages of Ultrasonic Leak Detection to Find Refrigerant Leaks!" video below or over at!

If you are looking to get your hands on the Accutrak VPE-GN Pro click here to learn more!

Published: 2/3/2021 Author: Brandon Price

About the Author: Brandon is the Director of Production of AC Service Tech LLC and has contributed to the creation of various resources developed by AC Service Tech. Brandon has several years of experience as an HVAC installation and service technician and has worked under Craig as an apprentice. Brandon is the primary web and graphic designer at & is the video editor for the HVACR videos which are posted at



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