central air drainage line not draining properly
My AC line continues to stop draining and the AC unit cuts off because the pan is full of water. I ahve had 2 AC companies and 2plumbing companies. The plumber has cut the line in several places because he thought it was clogged. However, through investigating, the line was not clogged, but the water remained in the pan and about 12-18 inches in the line. When he moved the line by picking it up slightly the water drained. I have had to go through this so my times that I have just about melted away because the attic is so hot right now. The plumber now recommends re-routing the line. I would have this done, however I don't want this to happen after I've spent a lot on money. It has worked for 12 years and I didn't have any problems. I have to leave it on 75 because if I raise it to 78 the pan starts to fill with water again. By the way, it is an old house that has been renovated. The line is vented to the gutter with a downspout.I think the plumber and AC people are perplexed. What seems to be the problem?