How can I properly drain heatpump condensate?
Adding a wye will provide a new location for water to drain. I would make sure your drain has no “traps” as a simple air bubble can cause backup. If you really want to drain someplace else there are condensate pumps. I do not recommend these when natural drainage is available because the pump will fail and then you are back with an overflowing pan. When I use pumps I add water sensor tape to set an alarm so I know about the problem before it ruins the Sheetrock/plaster.