Forespar Marelon Vented Loop Siphon Break Valve

The Forespar Marelon Vented Loop (also called an anti-siphon valve or siphon break) stops water and other fluids from siphoning back through marine plumbing lines. When the pump shuts off, the valve at the top of the loop lets air into the line and breaks the siphon. When fluid is flowing, the valve seals. Do not use it with fuel.

Key Features:

• Siphon protection: helps keep fluids from siphoning from tank to tank, or back into the boat from outside.
• Corrosion-proof Marelon construction: the vent and the loop are molded from Marelon, a glass-reinforced marine-grade composite, so neither will corrode.
• Duckbill one-way valve: designed to seal properly even when particulate matter is present in the fluid.
• Wide temperature range: Marelon operates from -40°F to +176°F.
• UV stabilized: the material resists deterioration in sunlight.
• Simple maintenance: activate the valves regularly and lubricate them twice a year with winch grease, Lanacote or water pump grease.

Common Applications: marine toilet (head) discharge systems, bilge pump outlets, engine aqua-lift and cooling systems, generator sets, air conditioning systems and ballast tanks.

Forespar offers vented loops in a range of hose sizes. Install the loop above the waterline. An optional vent barb assembly can replace the standard cap and duckbill so the loop can vent outside the hull through a 1/4" hose.