Hvac Condensate Drain Line Trap

The imc states that condensate drains should be trapped according to manufactures specs however wording was added in imc 307 2 4 1 that states that ductless systems must either have a check valve or a trap in the condensate line.

Hvac condensate drain line trap.

For the secondary drain system he installed a wet switch within the pan below the unit which will turn the unit off upon water detection. A p trap serves a very important purpose on an a c unit. It s similar to the trap under your kitchen or bathroom sink. For the primary condensate drain the installer piped 3 4 pvc into a condensate pump which will discharge into a nearby vanity sink prior to the trap via 3 8 vinyl plastic tubing.

The only code requirements for drain lines removing condensate from hvac equipment are. The drip pan connects to the condensate drain line which carries water out of the home. That is why in the summer your car drips water. The air trap concept has been incorporated into iapmo igc 196 2018 standard for condensate traps and overflow switches for air conditioning systems.

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 drain pan overflow or water droplet carryover into the duct system. Another sign your condensate lines may be clogged is if no moisture is exiting outdoors. All air conditioners have a special drain for this condensation. Air conditioning units pull a lot of water out of the air.

A for the installation of a trap in accordance with the unit manufacturer s installation and operating instructions. When the drip pan becomes full or clogged or the condensate line is clogged water can spill over the drip pan s edges onto the floor surrounding the unit. The hvac air trap allows liquid condensate to drain from the hvac equipment and simultaneously prevents air from entering or escaping from the equipment. See when moist air hits something cold the water condenses out of the air and collects on the cold surface.

Trap required in condensate line if the condensate drain line is under negative pressure e g upstream of blower as shown here a trap is required. While most manufacturers don t specify this on this gravity ductless drains it is something to look out for.