{"product_id":"lisnhlin-rv-vacuum-breaker-check-valve-replacement-571-1-2-npt-8-125-psi","title":"Lisnhlin RV Vacuum Breaker Check Valve Replacement 571 — 1\/2\" NPT, 8–125 PSI","description":"\u003cp\u003e\u003cstrong\u003eLisnhlin 571-VAC-CHK-A is a one-way vacuum breaker check valve designed to prevent backflow in RV black tank flushing systems, protecting your freshwater supply and stopping leaks.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eThis compact replacement check valve fits into the black tank flusher line and is commonly used between the freshwater source and the tank flusher on campers, travel trailers, and motorhomes. Built to handle typical RV water pressure and to replace cracked or leaking OEM parts, the 571 model keeps wastewater contained during flushing and helps maintain clean freshwater connections while on the road.\u003c\/p\u003e\n\n\u003ch3\u003eHow does this check valve stop backflow into my RV freshwater system?\u003c\/h3\u003e\n\u003cp\u003eThe Lisnhlin vacuum breaker check valve operates as a one-way device that allows water to flow toward the black tank flusher while preventing reverse movement. If pressure drops or a downstream fault occurs, the internal mechanism closes to block contaminated water from returning toward your potable supply. It’s an inexpensive safeguard for any RV flush line where cross-contamination would be a problem.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eOne-way internal valve design prevents reverse flow.\u003c\/li\u003e\n  \u003cli\u003eInstalls between freshwater inlet and tank flusher for direct protection.\u003c\/li\u003e\n  \u003cli\u003eHelps keep potable water lines separate from black tank discharge.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat are the installation requirements and thread size for the 571-VAC-CHK-A?\u003c\/h3\u003e\n\u003cp\u003eInstallation is straightforward: the part uses 1\/2\" NPT male threads on both the inlet and outlet and should be threaded into standard RV plumbing fittings. For correct operation it must be mounted at least 6 inches above the highest point of any item connected to the waste tank where the flusher is installed. Follow common plumbing practices—use thread sealant or PTFE tape and hand-tighten with a wrench to avoid overtightening.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e1\/2\" NPT male threads on inlet and outlet for common RV fittings.\u003c\/li\u003e\n  \u003cli\u003eMount at minimum 6\" above the highest connected waste-tank point.\u003c\/li\u003e\n  \u003cli\u003eUse PTFE tape or suitable thread sealant; tighten to secure but avoid stripping threads.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat water pressure can this vacuum breaker withstand, and is it durable for travel?\u003c\/h3\u003e\n\u003cp\u003eThe 571-VAC-CHK-A is designed to tolerate typical RV water pressures, rated to perform reliably between 8 and 125 PSI. Its construction is intended for repeated use in mobile environments, resisting pressure fluctuations and everyday wear. Replacing a worn or cracked check valve with this part restores efficient flushing and reduces the chance of leaks or wet floors in your vehicle.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eRated working range: 8–125 PSI to suit most RV systems.\u003c\/li\u003e\n  \u003cli\u003eDurable materials resist pressure cycling during travel.\u003c\/li\u003e\n  \u003cli\u003eDirect replacement for cracked, leaking, or faulty check valves.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eHow will replacing this part improve my black tank flush performance?\u003c\/h3\u003e\n\u003cp\u003eA fresh, functioning vacuum breaker ensures water flows only toward the black tank flusher, preventing back-siphonage and the unpleasant side effects of a malfunctioning valve—such as slow flushing, odors, or unexpected leaks. Swapping a degraded valve for the Lisnhlin 571 restores reliable flow control and reduces maintenance needs. It’s a small part that has a big impact on cleanliness and convenience in your sanitation system.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eStops leaks and prevents wastewater from reaching freshwater lines.\u003c\/li\u003e\n  \u003cli\u003eRestores consistent flushing pressure and flow direction.\u003c\/li\u003e\n  \u003cli\u003eReduces risk of wet floors or blocked lines caused by failing valves.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eWho is this for: RV owners, campers, and fleet technicians who need a dependable, easy-to-install replacement for a faulty black tank flush check valve. If you manage routine RV maintenance or experience leaking or backflow during black tank flushing, the Lisnhlin 571-VAC-CHK-A is a practical upgrade to protect your freshwater lines and keep your sanitation system working as intended.\u003c\/p\u003e\n\u003csection class=\"product-faq-snippet\"\u003e\u003ch3\u003eFAQ\u003c\/h3\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Can I install this valve myself in my RV?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: Yes. It has 1\/2\" NPT male threads and installs with standard fittings; use PTFE tape and mount at least 6\" above the highest connected tank point.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: What pressure range does the Lisnhlin 571 support?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: The valve operates reliably between 8 and 125 PSI, suitable for most RV freshwater systems.\u003c\/p\u003e\n\u003c\/div\u003e\u003c\/section\u003e","brand":"Lisnhlin","offers":[{"title":"Default Title","offer_id":55163423916375,"sku":"B0CR4414BR","price":34.87,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1050\/1524\/7191\/files\/lisnhlin-check-valve-front-view.jpg?v=1790344369","url":"https:\/\/britishgarage.co.uk\/products\/lisnhlin-rv-vacuum-breaker-check-valve-replacement-571-1-2-npt-8-125-psi","provider":"British Garage","version":"1.0","type":"link"}