P Trap Condensate Drain

Air was coming in from the outside and creating a dam which was preventing the con.

P trap condensate drain. If fan is located upstream of coil fan will pull water up drain line counter to water flowing down drain. Traps with insufficient height between the inlet and outlet design deficiency on draw through systems can cause the drain to back up when the fan is on possibly causing. The ac equipment is set on the slab floor or curb and it is the mechanical contractor s job to install a p trap. A central air system routes condensation through a u shaped trap located in the drain line just outside the air handler.

It s similar to the trap under your kitchen or bathroom sink. If fan is located before the coil in the system the fan will push small amount of air and water down condensate drain. A p trap is needed to block air and allow condensate to drain properly. See below for an image of a sink p trap which works the same way.

What is a p trap. See water won t flow up hill so the 180 degree turn in the drain causes water to get trapped in the bottom of. There is a major difference between using p traps on sanitary applications and condensate removal from an ac unit and that is. P traps have to be installed on a suction system so a p trap was added.

Air conditioning units are shipped from the factory to the job site without a condensate drain trap.