I need to buy and install a split AC and I have a small issue.

The AC has two copper pipes for refrigerant gas to flow through and one hose to eliminate condensation water, and normally, the hose should hang below the AC unit to let gravity take out the condensate water. But because of some load bearing walls (in which I'm not allowed to make any holes) I'm limited in the location where I can mount the AC units. Because of that, the copper pipes and the condensate hose have a weird route which isn't a straight downfall from the internal unit to the external one. They don't go above the internal unit or below the external one, but the general shape is that of an U where water can stagnate.

Is this a problem? The copper pipes transport gas so I think it doesn't matter what shape or route they take, but the hose will retain some water in the middle.

What are the rules to follow when arranging the condensate hose? I don't want to buy the AC units and find out that there will be problems with evacuating the water.

  • The basic rule is "don't create an air lock" so u-bends or tight bends are things that the manufacturer says don't do.... So, follow the installation instructions... – Solar Mike Jun 20 '19 at 14:17
  • The copper lines carry liquid in one, gas in the other but the are under pressure so no problem there. You could install a condensate pump to pump the water through the pvc. – Gunner Jun 20 '19 at 14:39
  • As mike says a u bend is not a good idea, this will be where stuff grows and plugs up, I don’t like pumps unless there is no other way because there will be pump failures within the life of the system if not several failures. If I had to make a u bend I would up size the recommended drain size and flush it several times a year to prevent blockages. – Ed Beal Jun 20 '19 at 14:51
  • Some people intentionally put a small U in the condensate line. This is maybe 8 inches of drop. I think this is either to restrict the flow of air out the condensate line or to provide a water seal to prevent air or bugs going into the a/c from outside. What would be the configuration/dimensions of your U? – Jim Stewart Jun 20 '19 at 15:42
  • If you would have U of more than a few inches in depth the air flow from the air handler might not have enough pressure to drive the water out. See google.com/… – Jim Stewart Jun 20 '19 at 16:18

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