The Proper Way to Install a Condensate Drain Line

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Things You'll Need

  • Measuring tape

  • Drill

  • Jigsaw

  • Drain pipe

  • Hacksaw

  • Pipe cutting tool

  • Sandpaper

  • PVC glue and primer

  • Solder and flux

  • Pipe material and bends (PVC or metal)

  • Pipe thread compound

  • Drain pipe flanges

Once you've completed installing a new air conditioner, your work isn't quite finished. Before you switch on the unit, you'll need to know the proper way to install a condensate drain line. These drain lines carry away condensation produced by the operation of the evaporator on the air conditioner unit. The key to this project is to measure out the path of the drain line properly, as this will tell you exactly how much pipe material you need.


Step 1

Turn off the power for the air conditioner unit where you will be installing the drain line.

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Step 2

Measure out the path that your drain lines will take from the drain pan to the drain field area. The drain field shouldn't be in a public area, such as a stairwell or driveway. It's best to route the condensation out into a lawn. Measure out a path for the primary and secondary drain line.

Step 3

Drill any holes as needed through walls in order to accomodate the drain lines. Holes in a wooden house can be started with a drill and then finished with a jigsaw. To drill a hole through a brick wall, drill several holes around the perimeter of the drain exit and then hammer out the hole with a chisel. Sand down the rough edges of the hole.


Step 4

Measure carefully the diameter of the drain line connection for the drain pan. This will give you the size of pipe that you need to use for the drain connections. In many locations, this will be 1/2-inch pipe.

Step 5

Use the measuring tape to measure and cut the pipe lengths to run from the primary and secondary connections on the drain pan to the draining points outside. Use a hacksaw on PVC or a pipe cutter on metal materials. Sand down any rough edges with sandpaper or a file. Dry fit the pieces together without glue or solder to make sure the pipes fit and route correctly. In order to drain properly, the pipes should drop at least 1 inch for every 3 feet of length.


Step 6

Connect the inlet flanges to the drain pan. Seal the threads on the flanges with pipe thread compound before you screw them together, one on the inside of the pan and one on the outside.

Step 7

Starting at the pan flange outlets, secure the pipe in place, either by gluing or soldering, until the pipes reach the outlet holes.

Step 8

Restore power to the air conditioner.


Never connect condensate drain lines directly into a sewer pipe.

The above steps are just a guideline. Always consult local codes in your area when installing a condensate drain line.


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