Why does AC unit need condensation drain trap

air-conditioningcondensation

I am modifying the drain pipe that drains my inside AC unit. When I purchased the home, there was an electric drain pump tied to the unit. Upon investigating why the unit needed one I found a pipe in the wall that used to drain the old AC system. The problem is the drain was too high in the wall to be used on the new AC when the previous owner replaced it.

So I opened up the wall and rerouted the pipe so it was at the same level. My problem is that the end of the drain is just barely low enough to create the minimum slope needed for water to drain correctly ( 1/4 inch drop per 1ft).

To make this work with a condensation drain trap, I was wondering if I could used the secondary drain coming off the unit as the main drain. This is because the secondary drain is about an inch higher then the main. If cant do this then I wont be able to use a condensation trap.

How important is the condensation drain and can I use the secondary drain rather then the main. Thanks guys!

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Best Answer

The trap in the condensate drain, prevents the unit from sucking air from; or blowing air into, the drain line. Without the trap, the condensate may not drain until the blower turns off. This could lead to the pan overflowing. So you can't remove that.

The secondary drain is typically for situations when the main drain is blocked, or otherwise insufficient. In some units, condensate only reaches the secondary drain when the pan overflows. If this is the case, using the secondary drain as a main, would allow water to sit stagnant in the pan. So you probably won't be able to use it as the main drain, but it may vary depending on the unit.