Lisnhlin Brass RV Vacuum Breaker Check Valve 1/2" NPT Male — Upgraded 8–125 PSI Replacement for b&b Model 571

Lisnhlin's 571-VAC-CHK-A is an upgraded brass vacuum breaker check valve designed to replace leaking b&b Model 571 units and protect your RV's freshwater from backflow.

If your camper's black tank flushing line is allowing waste or wastewater to siphon back toward the freshwater source, this brass check valve provides a durable, straightforward fix. Built to fit between the freshwater inlet and the tank flusher, the 571-VAC-CHK-A is a direct service replacement engineered for long-term reliability during road travel and campground use.

How does this valve stop backflow into my freshwater system?

The valve functions as a one-way vacuum breaker and check valve, mechanically preventing water from flowing backwards into the freshwater line. When pressure drops or a siphon effect occurs, the internal check closes to block contaminated water from re-entering your potable supply.

• One-way flow design prevents reverse flow and back-siphonage.
• Installed between freshwater inlet and black tank flusher for isolation.
• Reduces risk of cross-contamination during flushing operations.

What are the material and pressure specifications?

This upgraded unit uses brass construction to resist corrosion and handle typical RV water pressures safely. The valve is rated for 8–125 PSI, making it suitable for most RV potable water systems and campground hookups.

• Solid brass body for improved durability over plastic alternatives.
• Pressure capacity: 8–125 PSI to cover common RV water scenarios.
• Designed for repeated use without performance degradation.

Is installation complicated and what fittings are required?

Installation is straightforward: both ends come with 1/2" NPT male threads that fit standard RV plumbing adapters and lines. Positioning matters — the valve must be mounted at least 6 inches above the highest point of any device connected to the waste tank flusher to operate correctly.

• 1/2" NPT male threads on inlet and outlet for simple plumbing connections.
• Mount at minimum 6 inches above highest connected point to prevent siphoning.
• No special tools required for most installations beyond common pipe wrenches and thread sealant.

Will this part fit my RV or camper model?

The 571-VAC-CHK-A is designed as a replacement for b&b Model 571 vacuum breaker check valves and works with many RVs, travel trailers, and motorhomes that use the same black tank flush arrangement. Always confirm thread size and clearance before purchase to ensure compatibility.

• Direct replacement for b&b Model 571 check valve assemblies.
• Compatible with most black tank flush systems that use 1/2" NPT connections.
• Works across a broad range of RVs, campers, and trailers as a standard fix for leaks.

Who is this for: The Lisnhlin 571-VAC-CHK-A is aimed at RV owners, repair technicians, and DIY campers who need a reliable replacement for a cracked or leaking vacuum breaker in their black tank flushing system. It suits anyone seeking a durable brass alternative to plastic valves, a straightforward field-service part for preventing backflow, or a preventative upgrade to protect potable water during tank maintenance.