Forespar MF 840 Vented Loop - 1-1/2"

The Forespar MF 840 Vented Loop in 1-1/2" is an essential anti-siphon device designed to protect your marine sanitation system and prevent raw water from flowing backward into your head tank. This product is particularly useful for boaters who want to ensure their systems remain functional and free from contamination during heavy weather or extended periods of inactivity.

Engineered with a high-loop design, the MF 840 positions the vent opening above the maximum water level of your tank, ensuring that atmospheric air can always enter the discharge line when needed. This vented loop features a durable construction that withstands years of exposure to saltwater and UV degradation, making it ideal for topside installation. The integrated vent valve operates under negative pressure and seals under positive discharge pressure, allowing for normal gravity-fed drainage while preventing backflow.

Ideal for cruising sailboats, fishing vessels, and cabin cruisers, the Forespar MF 840 is compatible with traditional overboard discharge systems and those transitioning to compliant holding tank configurations. Its straightforward installation process allows boaters to position the loop in the overhead or cabin ceiling above the tank, ensuring optimal performance and reliability.