The Difference Between Inline Check Valves and Condensation Traps
Condensation traps are commonly required for heat pumps, straight cooling systems, and even high-efficiency condensing gas furnaces. Some manufacturers even include them to ensure a trap is installed.
Due to the scope of the installation, things work a bit differently when it comes to ductless mini-split installations. However, traps are still a requirement.
The 2015 International Mechanical Code: 307.2.4.1 Ductless mini-split system traps, above, states:
Ductless mini-split equipment that produces condensate shall be provided with an inline check valve located in the drain line or a trap.
This 2015 code amendment remains in the 2024 International Mechanical Code.
Although the code specifies "mini-split," some inspectors have broadened its interpretation to include all wall-mounted ductless units, such as multi-zoned systems and VRF units. This is because the basic construction of drain lines for wall-mounted units remains consistent across various equipment types.
A standard trap would be difficult to install on a wall-mounted ductless unit so an inline check valve designed specifically for ductless products would be a much better solution.
Inline check valves offer the same protection as a traditional trap but instead of using the condensation to provide the “seal”, it uses a mechanical process. The inline check valve allows moisture to drain and closes afterward preventing any kind of outside infiltration, such as air, dust, insects, and even odors, through the drain line.
Inaba Denko’s inline trap, the DHB, is tailored for ductless applications. Made of acrylic resin, this transparent piece allows for visual inspection making maintenance a breeze. Easy to use, it attaches to the drain line and stays securely in place.
Since each installation has its characteristics, it's important to verify with your local code authority for any specific regulations that might exceed the standards set by the International Mechanical Code.
Learn more about this from Kerry McIntyre in our Ask a Trainer video below:
