1. To avoid oxidation inside the tube, always pass nitrogen through the tube when welding.
2. Use new, clean tubes for the refrigerant. Handle the tubes carefully to prevent moisture and dirt from entering the tube.
3. Always use a torque wrench to loosen and tighten the flange nuts. It is not possible to tighten the nut properly with a simple wrench. Tighten the nut to the manufacturer's torque.
