• Welds made without the passage of nitrogen inside the tubes, leads to the formation of russeting, which is not easily removed by R141b;
• Nitrogen is much cheaper than R141b. There's no reason not to use it.
• R141b should only be used for final cleaning.
• Copper tubes should have the burrs removed and the ends sanded.
• Whenever the system is opened, the dryer filter should be replaced.
• After engine burn, change the oil from all circuit compressors, filter drier and install post-burn filter in the suction if necessary. The acidity resulting from the burn will burn other compressors that are interconnected in parallel if nothing is done in the system.
