PLP-Series HVAC Air-Trap — The first AC condensate trap to use air pressure developed by the AC fans to prevent conditioned air from entering or leaving the unit.

A new concept in condensate trap design permits condensate removal from AC or other condensing equipment while blocking airflow all year and requires only 2 7/8” height for positive 0-40” WC pressure. Will never “dry out” or freeze because it does not depend on water to seal, only fan pressure.

The PLP trap is the first AC condensate trap to use air pressure developed by the AC fans to prevent conditioned air from entering or leaving the unit. For a hundred years the P-Trap, a carryover from use on toilets and sinks, has been used on AC equipment to prevent air loss. Unlike the P-Trap, the PLP was designed specifically for HVAC equipment and does not require standing water to prevent air leakage. AC equipment produces condensate mostly during summer. The remainder of the year little or no condensate is produced, and the P-traps are dry most of that time. When they do have water, the bottom of the trap is prone to develop sludge and growth. The PLP operates dry when no condensate is being produced and uses a levered, horizontal pancake designed float-valve with a mechanical advantage about a pivot point. This allows the PLP to require less than 3 inches of height for up to 40 inches WC pressure instead of the 8 to 60 inches required for a standard P-Trap.

Because positive pressure, resulting from blow through units, does not create problems associated with negative pressure condensate traps, such as sucking air and blowing condensate over the cooling coil compartment, positive pressure traps are left out of the drain line. This results in air that has just been cooled or heated being blown to ambient and unconditioned ambient air of equal amount being drawn into the space through the building envelope or ducting.

Another problem facing engineers and contractors that prevent using a positive trap is the height required by the trap to enable it to contain enough condensate to prevent dry-out and leakage of conditioned air during the entire year. Also, there are essentially no universal mechanical codes that require traps on condensate lines that would prevent loss of conditioned air. The Series PLP Air-Trap solves all the problems just mentioned. It can operate at positive pressures ranging from 0 to 40 inches WC, is only 2 7/8” from center line of drain outlet to roof or slab, never dries out, and never leaks air.


For more information, please contact Des Champs Technologies at:

ph: 540 228 1967 or info@deschampstechnologies.com