1. Connect piercing valves (if there are no access valves in the system) and discharge the system leaving the valve open.
2. Clean the puncture with sandpaper and wipe it with a rag soaked in acetone to remove all contaminants from the area to be silver-brazed.
Be thorough in this step; otherwise, the solder will not adhere properly.
3. Seal the hole by silver brazing.
4. When the leak is sealed, replace the filter-drier (see fig. 76) and connect a manifold gauge to the valves and recharge the unit with the proper refrigerant. (About 3 oz for residential units, and for commercial units, just enough to raise the pressure in the tubing above atmospheric pressure.) Then close the valves; start the unit and check the system using a leak detector to ensure there are no more leaks.
NOTE: It is best to check for refrigerant leaks in the low side when the unit is not running as the low-side pressure rises during the off cycles.
5. Follow the procedures given for evacuating and recharging the system.
6. Sandpaper all the new silver-brazed joint to ensure no flux residue is left in the tubing. Flux contains acid and corrodes copper if left on the tubing. Then vacuum the system to force out the moisture that penetrates the system during the repair and recharge the unit with the proper amount of refrigerant.