& melts water & will refrost but everything works fine

That is the suction line coming from the coils in the freezer that is frosting up. That line can frost up, but it can indicate that the freezer is not defrosting enough. If the unit works well then I would not worry much about it. The main thing you should keep a constant watch on is dirt on the coils under the unit. These coils will fill up with dirt and cause your unit to burn up from overheating. They must be cleaned twice a year by removing kick plate on front and removing cover on rear and blowing out dust and dirt, and best washing off coils with a light spray of water (with unit unplugged before you do any work). After cleaning it put rear cover back or it will not work. Keeping the coils clean will prevent most problems. DrTom4444

When the line frosts up & melts it melts enough to cause damage to the basement ceiling could it be something else?

You can prevent this by drying it thoroughly while it is off and putting some small rubber pipe insulation (called Armaflex) around the line and sealing it to the cabinet where it goes in the unit and against the compressor. Use GE Silicone Rubber caulk-it's about $6.00 a tube. The cheap stuff will not work. It must be air tight. This will stop all condensation from occurring. That is the main reason you see AC lines insulated-to prevent condensation from dripping off the suction line. Normally, you don't have a lot of condensation, but maybe you have a lot of humidity in your house. This will solve the problem. DrTom4444