Red Dye Leak Detector

A red dye leak detector is available to aid diagnosis of air conditioning refrigeration system problems. The dye is mixable both in the liquid refrigerant and in the compressor oil. The dye leaves the compressor in the oil which is carried along with the hot refrigerant gas. In the condenser, the dye and the oil are dissolved in the liquid refrigerant. In the evaporator, the dye remains in the oil when the refrigerant boils into a vapor. It is then returned with the oil to the compressor by the suction pipe.

Leaks show up in a matter of minutes on the suction side as easy-to-see red stains. Leak detection in the condenser and the liquid pipe may be slower and can appear as a faint pink color due to the low amount of red dye in the oil. In most cases. a bright red color (usually oil) will appear at the point of leakage. Most leaks show up in a short period of time - but some may take up to 24 hours before they possess enough color to become visible. If leaks develop in parts of the system which are difficult to see, or if dirt and oil have gathered around connections, the area can be wiped with a white cloth or paper towel to pick up any traces of the red dye. The red dye should be wiped up after repairing a leak so that the next technician does not think that he has found a leak in the same location.

If new dye is to be added to Refrigerant- 12, it must be charged as a liquid. If charged as a vapor, the dye will be left behind as a liquid in the container. Only GM-approved dye should be used. Other dyes may alter the chemical stability of the refrigerant or may curdle and clog the expansion valve or damage the compressor.

Red dye leak detector can stain some materials. It may be necessary to clean the dye from floors, hands and clothing. Use the following suggestions to prevent red dye stains:

^ A cloth or paper towel should be wrapped around couplings and fittings before hoses/pipes containing red dye leak detector are disconnected.
^ Valve or hose outlets should be surrounded with several layers of cloth before they are vented.
^ Valves should be opened slowly. This will keep liquid refrigerant and oil from blowing out of the refrigeration system.
^ Gloves and eye protection should be worn.
^ Surfaces should be wiped quickly with a clean cloth.

Solvents that will help in removing the red dye include lacquer thinner, Virginia No. 10 solvent, Stoddard solvent and other similar solvents. The solvents are most effective if used right away. Most of the dye can he removed from clothing by conventional laundering methods.