Service Tools
Chapter 4 Page 12
Leak Detection
No sealed system is satisfactory unless it is absolutely leakproof. There are three common methods of detecting refrigerant leaks :
1. Halide torch - No Longer Use this type of leak detection
2. Electronic leak detectors
3. Bubble solutions
The Halide torch leak detector operation is based on the fact that when burning refrigerant is passed over a hot copper plate or reactor, the flame changes color. Fuel for the torch may be either acetylene or propane fuel. The detector fits into the
torch handle. Primary air to the burning flame is supplied through the sensing hose. Ordinarily the flame will be a clear blue color. If, however, the end of the sensing hose should be passed near the area of a refrigerant leak, the refrigerant will be drawn in with the primary air and burned in the flame. As it passes through the copper reactor, a chemical reaction takes place, causing the flame to change color. A small refrigerant leak causes the blue flame to tint green. A large leak causes the flame to turn a livid purplish blue.
CAUTION: The fumes from burning refrigerant are poisonous and should not be inhaled.
*Warning due to the new refrigerants containing Butane and or Propane that are being used to replace R134a and other refrigerants TMM Academics strongly discourages any one from using this type of leak detection. The above is for informational purposes only.
Leak Detector User Manual
Electronic Leak Detector
Electronic leak detectors are frequently used in leak testing. Typical testers are shown in Figs. 39 and 40. They are very sensitive and detect leaks as small as ½ ounce per year. Always follow the instructions from the manufacturer of the tester being used. The tip of the probe should be placed slightly below, or as near as possible to, the suspected leak. Allow 3 to 5 seconds for the unit to react.
Bubble Solution
The Halide torch and the electronic leak detector, when used in areas insulated by foamed urethane, will give a false reading because a fluorocarbon similar to a refrigerant is used as the expanding agent in the manufacturing process. In such cases it is necessary to use a bubble solution to locate leaks.
Such solutions are commercially available or can be made up with liquid dishwashing detergent. Simply apply the solution to the area being tested; if bubbles form, a leak is indicated. This method of leak testing is not restricted to foamed-urethane areas. When testing is completed, remove all bubble solution from the tubing and unit. If this is not done, corrosion is likely to occur.
