Should the drip line from the inside unit of a heat pump have a P-trap when the line is routed directly outside?
A recent home addition included a heat pump with the inside unit located in the attic. The drain line has a P-trap right at the inside unit. Than the line runs about 18' to an exterior wall and 17' down the wall to a point about 1' above grade.
My concern is that, over time, sediment will not be flushed in this low volume application and cause leakage problems in the long term.
Do you guys use P-traps in similar applications? If not, would you remove an existing one?