Other Methods

• You might spot a leak with a visual inspection of the A/C system--look for wetness around lines and fittings as well as porous or damaged hoses. If a leak is suspected, one way to verify the location is to use a bubble-type detector. To use this type of detector, apply its special solution directly on the possible leak points. Any leaks will show up as bubbles or foam. A similar type of leak detector is an internally charged leak detector, which is a brightly colored agent that can be introduced into the system through charging (service valves and a recovery unit are required to use an internally charged leak detector). Leaks will show up as brightly colored spots where the leak is located. Another method, which is not recommended, is the torch detector. By bringing a gas torch close to the suspected leak, you can see if the flame changes color, indicating the presence of refrigerant. Be aware that when refrigerant is burned, it turns into highly toxic phosgene gas, so use this method only in a well-ventilated area.
  
  

Electronic Refrigerant Leak Detectors

• The tool of choice for most technicians for hunting down a refrigerant leak is the hand held electronic refrigerant leak detector. This device has a special sensor and an electronic amplifier that you can bring to the vicinity of practically every part of your A/C system with the help of a flexible probe. The electronic leak detector will beep or flash if leaking refrigerant is detected. If you're not sure where the leak might be, check these places first: along the bottom and sides of the condenser, compressor front seal, line fittings, drier connections, any hose-to-line connections, and at the evaporator. If a leak is found at a line fitting, often the leak can be fixed by tightening the fitting. Check for the leak again after tightening the fitting.