A heating coil's cooling leg to steam trap should be at least how long?

• A. 5 feet
• B. 3 feet
• C. 7 feet
• D. 9 feet

Answer: (A)

The main idea is that the cooling leg must give condensate a reliable gravity-fed path to the trap while keeping steam out of the trap line. A longer leg provides enough distance for condensate to separate from any entrained steam and to drain down smoothly, rather than riding along with steam or flooding the trap. This helps prevent steam carryover into the trap and ensures the trap receives steady condensate flow, reducing the risk of improper draining or water hammer.

Five feet is a practical minimum that offers sufficient length and slope for proper drainage and steam separation. If the leg were shorter, condensate could be carried into the trap with steam or fail to pool properly, compromising trap operation and system efficiency.