I thought p-traps were always used on condensate lines from A/C air handlers (evaporators). But the installation instructions for my Daikin ductless mini-split does not show or call for a p-trap in the drain line. If I install one next to the air handler, will it cause me problems? Is it even needed? Perhaps there is p-trap setup somewhere inside the air handler. BTW, the unit is a heat pump system, if that matters. Thanks.