How To Install A P Trap

When installing a P trap in a condensate drain line for your air conditioning system it is important to follow some basic practices to avoid potential problems and achieve proper drainage.

It is important to install a P trap so that the inlet side of the trap is about one pipe diameter higher than the condensate trap outlet. If the p-trap outlet is too high the drain line will not work properly.

P trap Definition

A P trap is a device used to prevent the escape of gases from sewer systems or used on air conditioning equipment to prevent condensate from the ac unit from over flowing the evaporator drain pan.

On many air conditioning systems, a negative pressure is created inside the air handler. Without a condensate trap, ac condensation can be prevented from draining through the air conditioner drain because air is being drawn in through the drain opening.

A P trap collects condensate from the drain pan in the trap and prevents air from being drawn in through the drain opening. Even if the air conditioner drains into a condensate pump you still should have a p trap installed at the drain pan outlet.