"Ctal" wrote in message
oups.com...
We've got an attic AC unit. Over the past week the AC has shut down
(wonderful in our 90+ summer weather). It's doing this because of a
kill switch in the drip pan. As the drip pan fills up, it raises a
float on the switch and shuts the unit off.

By literally bailing the water out of the drip pan, we can get the AC
restarted. Of course this is not a practical solution.

From reading here, I believe the problem is caused by the primary drain
line being clogged? Can someone walk me through some steps to unclog
this line?

The system has two PVC pipes coming out of the attic unit. One takes a
short bend and opens into the drip pan, this is the one thats seeing
the action at the moment. The other line seems to run towards the side
of the house, presumably to connect with the drain line off of the
bathroom in that direction. This line has an opening at a Y joint near
the AC unit. One part of the Y continues to the drain line as
mentioned above and the other part of the Y is a short piece of pipe
open to the attic. Thanks in advance for any suggestions.

Where I live they do not put floats in the pans.
Your air handler should have one drain going outside, directly from the
unit. The pan should have its drain going outside as well. Usually the air
handler drain is low on the outside wall and the overflow pan is high. They
do that so it will be noticed. The air handler should not be dumping into
the pan.
A shop vac may be able to blow out the blockage. Other posters had good
suggestions on cleaning the pan.

I do not know why anyone would use both drain holes from a air handler. One
is enough. The manufactures supply usually 2 to cover all of the
installation configurations.

If the house is new it might be time to call the contractor and have them
correct what sounds like an incorrect installation.

"Y" are not legal if they ever were where I live. Phoenix