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Electronic Refrigerant Leak Detectors and Methods

Other methods include portable, hand-held electronic devices, and fixed system monitors. These are recognized as the quickest, cleanest methods.

A question that's commonly asked is, “Are leak detectors helpful in detecting leaks with all of the new refrigerants and R-22 replacement blends?” With the influx of new refrigerants, following the Environmental Protection Agency-mandated phase-out of chlorodifluoremethane (R-22) and other mandates for CFCs, HCFCs and HFCs, detection products and methods continue to be a challenge. With that in mind, many instrument companies have developed and improved their products to meet the current and even future needs with the refrigerant evolution.

Superior Sensing Devices

State-of-the-art leak detectors are able to identify all CFCs, (those containing chlorine), HCFCs (those containing fluorine) and HFCs (non-ozone-depleting refrigerants and compounds), plus bromine gas (found in HBFCs) and halogens. A superior portable leak detection tool will accurately detect and may identify the smallest of leaks. The ability to target the gases and the severity of the leak is the key to a great detection device. Reliability, longevity, serviceability, and cost should also be considered, yet initial cost alone may not be the best deciding factor.

Detector sensing devices to consider include:

Corona. This is a charged electrode which causes a charged “corona” or “corona arc”. As refrigerant contacts the corona or arc, the charge is broken and the response is indicated on the detector. This detector can be easily contaminated by dust, dirt, oils, and moisture. False signals can also be caused by those same contaminates as well as by high hydrocarbon exposure, smoke, or electrical interference.

A heated diode uses a heated sensor. When it's exposed to refrigerant gases, electrical resistance is interrupted, which sends a signal to the instrument. The reading tells the technician the severity of the leak. Heated diode sensors have an enhanced sensitivity to HFC and HCFC gases. They're built to withstand high concentrations of refrigerant gases, and they clear quickly. This unit typically works well on all refrigerants and blends.

Infrared detectors are moderate- to higher-priced, yet they have a longer sensor life, and pose minimal problems. These detectors emit infrared light energy through a chamber towards an infrared detection target. A filter produces a unique light spectrum. Gases are drawn across the spectrum and energy is absorbed by the chemical. This decreases the amount of light reaching the end of the camber, where an infrared detector senses a temperature change.

This type of detector works well on all refrigerants and blends with minimal false indications.

Key to Infrared Functionality

Getting the refrigerant to pass over the sensing element is a key to accurate infrared detection. A displacement pump or fan is often used to provide quick response. Sufficient power is needed for detectors to function correctly, and operational sensors are required. Sensitivity adjustment to refrigerants and to background contamination are a consideration with electronic leak detection. Manually adjustable devices can also be adjusted by the technician.

Some detectors have self-zeroing functions and can be adjusted for background gases. The technician should understand if a detector's sensitivity level can be made manually, or if the unit is self zeroing.

Today's detectors are valued tools, especially when combined with the technician's patience and technical expertise. However, it's also important that the technician read and follow the directions, and ask questions as needed.

Also, remember that manufacturer support is usually easy to find.

Ken Kimball is a certified HVACR specialist in heating, refrigeration, gas detection, and energy conservation. He's instructed programs across North America. He has served with the Bacharach Institute of Technical Training for 10 years. Ken and his wife Sue Kimball are owners of ksKimball, Rapid City, SD. ksKimball provides HVACR instruments, CO detection and combustion instruments, calibration and training. He can be reached at ken@kskimball.com.

A Sampling of Leak Detector Manufacturers

• Bacharach Inc., Pittsburgh PA; 800/736-4666; bacharach-inc.com;
• CPS Products, Hialeah, FL; ; 800/277-3808; cpsproducts.com
• Fieldpiece, Anaheim, CA; 714/634-1844; fieldpiece.com
• Fluke, Everett, WA; 800/443-5853; fluke.com
• General Tools & Instruments Co., NY, NY; 212/431-6100; generaltools.com
• Inficon, E. Syracuse, NY; 315/434-1100; inficon.com
• UEI, Beaverton, OR; 800/547-5740; ueitest.com