Leak detection is a very important part of the service and maintenance of systems that use gases under pressure. The obvious application is the use of refrigerants in air conditioning and refrigeration. Others include natural gas for heating, nitrogen, oxygen, compressed air and CO₂.

In fact, with the advent of new refrigerants and the containment and handling that they require, gas leak detection has taken on a more significant role in daily hvacr service. And, there are several methods of leak detection available, including electronic devices, internal system dyes, and chemical gas leak detectors.

With regard to chemical leak detectors, it is important to select products with the appropriate features. Look for products that have the proper viscosity to remain on the surface and facilitate the formulation of bubbles.

And, at the same time, they need to be non-corrosive to the metal surfaces of the piping and fittings, and functional at low temperatures (freeze-protected), as well as elevated temperatures.

Application characteristics

Corrosivity: One of the most important features for a chemical gas leak detector is that it remains noncorrosive to the applied metal surface. Even after the technician wipes the fittings and joints, some residue of the leak detector will invariably remain, making it imperative that the product is noncorrosive.

Viscosity: The important distinction here is thickness vs. viscosity. A thick product is certainly viscous, but not necessarily a quality leak detector. Look for leak detectors with good viscosity, enabling them to remain on the metal surface and support long-lasting bubbles. Their viscosities should be achieved without the use of soaps.

UV lights: One of the other leak-detection tools used today is the internal fluorescent dye. This material is injected into a system, and leaks are ultimately detected through the use of a black light as it illuminates the fluorescent material. In these instances, look for a gas leak detector that will not leave any residue (fluorescent) that would otherwise set off the black light.

Freeze-protection: Top-quality gas leak detectors will be formulated with ingredients such as alcohol, glycols, or other compounds to lower the freeze point of the product, as well as raise its boiling point. This can be important to the technician, either because low-temp applications are involved or because storage in low-temperature environments could occur.

And, not only should the product be freeze-protected, it should also be freeze-thaw stable so if its freezing point is reached, it will remain functional after thawing.

Solids content: Chemical leak detectors will be amine-based, caustic-based, or made with a synthetic surfactant. Look for amine-based products with good viscosity and freeze-protection.

For more information, contact Nu-Calgon Wholesaler Inc., 2008 Altom Court, St. Louis, MO 63146-4151; 314-469-7000 or 800-554-5499.