HVAC Service: Leak Detector Tips & Tricks

If you work with large HVACR systems, you know one thing: they all leak at some point. Finding and fixing those leaks is critical to maintaining a healthy system. But before you can fix a leak, you need to find it. That’s where leak detectors come in.

If your HVAC system loses refrigerant, the first tools to use are your eyes and ears. Start by looking around for oil spills and listening for leaking holes near welds or other joints. If you don’t see or hear anything, the leak is probably very small. Soap bubbles and UV dyes are two effective ways to detect leaks, but they also have drawbacks. First, they can both be messy. In addition, you usually need a direct line of sight to see small leaks.

Leak Detector (002)Fieldpiece InstrumentsInfrared, heated diode and ultrasonic sensors are three versions of leak detectors that can immediately detect the presence of refrigerant. However, they can be extremely sensitive to small fluctuations and must be used slowly and methodically. These detectors are so sensitive that they can detect leaks as small as 1 gram of refrigerant per year. You can’t find a leak that small by waving your detector around the room. If you or the detector move a lot, or if there are small drafts in the room or even temperature changes, these are all elements that can affect the air and gas flow, making the leak more difficult to detect.

Infrared, heated diode and ultrasonic sensors are three versions of leak detectors that can immediately detect the presence of refrigerant.

Since refrigerant is heavier than air, it flows down from the leak and settles in low areas. It also thins within seconds. If we know how gas works, we can find the source of the leak. When your electronic detector senses the presence of refrigerant, it beeps or lights up. Once you have detected the presence of refrigerant, start slowly moving your detector from low to high points until the detector stops beeping. By doing this repeatedly, you can pinpoint the location of even the tiniest pinhole leakage.

How slowly should you move the detector? About three centimeters per second. Yes, that’s really slow. But this deliberate, methodical move ensures that you don’t create a breeze that affects the detection of a leak. It also ensures that leaking refrigerant has sufficient time to reach the sensor and react. To confirm that you have found the leak, move the detector to clean air and back over the suspected leak location to cause the detector to alarm again.

Leak detectors are becoming more and more sensitive, but the best way to take advantage of these new developments is to make sure you always use them correctly.

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