What setting do you use on an indoor air conditioner in Florida to keep the pipe inside from freezing up?

You most likely have one of two things: Indoor air flow. Your system is designed to deliver a certain amount of air flow through your coil. If your filter is extremely dirty, or your inside evaperator coil is dirty, or some of your registers closed. In Florida, you may have a clear fungus in your coil that is not easy to detect without proper knowlege. Also your duct work may not be installed correctly or adequately sized for your system. That possibility is answered by has it ever worked properly? If airflow is not the problem, then the next most likely answer is the refrigerant charge is incorrect.