Marine Toilet Vented Loop (Anti-Siphon Valve) – Ø19/25/38 mm

The vented loop (anti-siphon valve) is a crucial part of any reliable marine toilet installation. Its function is to prevent a continuous siphon effect where seawater or waste can keep flowing into the system even after flushing is finished. This vented loop automatically admits air into the hose once it senses a vacuum, thereby stopping the unwanted flow.

Usage & Benefits:

• Install the valve at the highest possible point above the boat’s waterline. It is typically placed inline on the hose running to the hull outlet or to the toilet’s seawater inlet.
• Use the Ø19 mm model for the intake water hose (e.g., for smaller toilets using 3/4" hose), Ø25 mm for systems requiring 1" hose, and Ø38 mm for the discharge hose of most standard marine toilets (1-1/2").
• This valve is suitable for both manual and electric toilets; it can also be used in other onboard systems (e.g., shower drains or generator cooling lines) where a siphon break is needed.
• The white body blends discreetly with the yacht interior and allows easy inspection and cleaning when necessary – the cap can be removed to clear the vent opening of salt or debris.
• Sail with peace of mind: by installing this anti-siphon valve, you eliminate the risk of your boat flooding through the toilet, especially in rough seas or when the vessel heels.