GROCO Bronze Vented Loop - 1" Hose

The GROCO Bronze Vented Loop for 1" hose (model HVL-1000) is a marine-grade anti-siphon valve engineered to protect sanitation and engine exhaust systems from unwanted backflow while preventing odor escape. Constructed from bronze for superior corrosion resistance in saltwater and freshwater environments, this vented loop allows air entry to break the siphon effect without permitting air or odors to exit the system—a critical distinction for vessel owners and marine operators managing bilge, gray water, or exhaust discharge.

The HVL series features an oversized vent valve designed to remain clog-free under normal operating conditions, ensuring reliable performance over extended service intervals. The valve's threaded 1/2" NPT port accepts a barb fitting, enabling overboard venting when required by system design or local regulations. For applications where overboard venting is mandatory—particularly in engine exhaust systems—this configuration provides a compliant solution that maintains anti-siphon protection while meeting discharge standards. The 1" hose connection accommodates standard marine hose sizes and fittings common to recreational and commercial vessel plumbing.

This product is essential for boat owners, marine technicians, and system integrators installing or upgrading sanitation or exhaust systems where siphon prevention is non-negotiable. The bronze construction ensures longevity in harsh marine conditions where dissimilar metals and salt exposure degrade lesser materials. Proper installation at the highest point of discharge lines ensures the vent loop functions as designed, protecting both system integrity and compliance with ABYC (American Boat and Yacht Council) marine standards.