{"product_id":"lisnhlin-rv-vacuum-breaker-check-valve-571-vac-chk-a-for-b-b-model-571-1-2-npt-prevents-black-tank-flush-backflow","title":"Lisnhlin RV vacuum breaker check valve 571-VAC-CHK-A for B\u0026B Model 571 — 1\/2\" NPT, prevents black tank flush backflow","description":"\u003cp\u003e\u003cstrong\u003eLisnhlin 571-VAC-CHK-A is a direct-replacement RV vacuum breaker check valve that prevents backflow into your freshwater supply and stops leaking black tank flush systems.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eIf your camper, travel trailer or motorhome has a leaking or failed check valve on the black tank flush line, the Lisnhlin 571-VAC-CHK-A offers a straightforward swap to restore one-way flow. Engineered to sit between the freshwater inlet and the flusher, this check valve keeps wastewater from siphoning back into clean water lines and reduces messy spills during flushing. It’s built for rugged RV use, tolerating typical water pressures and fitting standard plumbing threads for a quick install.\u003c\/p\u003e\n\n\u003ch3\u003eHow does the Lisnhlin check valve stop backflow into my freshwater system?\u003c\/h3\u003e\n\u003cp\u003eThe 571-VAC-CHK-A contains a one-way mechanism that allows fresh water to flow toward the black tank flusher but seals closed if pressures reverse. This prevents contaminated water from being drawn back into the freshwater line during siphoning events or when the flusher line is blocked.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eOne-way check design prevents back-siphonage.\u003c\/li\u003e\n  \u003cli\u003eRated to handle typical RV water pressures (8–125 PSI).\u003c\/li\u003e\n  \u003cli\u003eSits between freshwater inlet and black tank flusher for direct protection.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWill this valve work with my RV’s existing plumbing and how easy is installation?\u003c\/h3\u003e\n\u003cp\u003eThe valve uses 1\/2\" NPT male threads on both ends, matching common RV black tank flush fittings and making it compatible with many B\u0026amp;B Model 571-style systems. Installation is simple for anyone comfortable with basic RV plumbing: thread it into the line, ensure it’s installed at least six inches above the highest connected waste item, and check for leaks.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eStandard 1\/2\" NPT male threads for broad compatibility.\u003c\/li\u003e\n  \u003cli\u003eSimple screw-in installation—minimal tools required.\u003c\/li\u003e\n  \u003cli\u003eInstallation height requirement: minimum 6 inches above the highest waste connection.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat durability and performance can I expect on the road?\u003c\/h3\u003e\n\u003cp\u003eConstructed for use in RV systems, the Lisnhlin check valve is engineered to endure normal campsite water pressures and routine use. It resists leaks and cracking that cause wet floors and smelly compartments, helping your black tank flushing system operate reliably over time.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eDesigned for pressures from 8 to 125 PSI for reliable operation.\u003c\/li\u003e\n  \u003cli\u003eSolid construction to replace cracked or failing OEM valves.\u003c\/li\u003e\n  \u003cli\u003eReduces the chance of contaminated water and messy leaks during flushing.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eHow will replacing the valve improve my black tank flush experience?\u003c\/h3\u003e\n\u003cp\u003eSwapping in a fresh 571-VAC-CHK-A restores proper one-way flow, preventing the common symptoms of a bad valve: backflow, blockages, and water on the camper floor. A working valve keeps the flush line functional and your freshwater separate from waste, saving time and cleanup after flushing.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eStops leaks that soak the RV floor during flush cycles.\u003c\/li\u003e\n  \u003cli\u003ePrevents contaminated water from reaching freshwater lines.\u003c\/li\u003e\n  \u003cli\u003eRestores efficient flushing and reduces maintenance headaches.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eWho is this for: RV owners, service technicians and DIYers who need a dependable replacement for a leaking or cracked vacuum breaker\/check valve in black tank flush systems. It’s especially useful for campers using B\u0026amp;B Model 571-style flushers, travel trailers and motorhomes where one-way protection and easy installation are priorities. Choose the Lisnhlin 571-VAC-CHK-A when you want a simple, durable fix that brings your black tank flusher back to reliable service.\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: Is the Lisnhlin 571-VAC-CHK-A compatible with B\u0026amp;B Model 571?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: Yes. It’s designed as a direct replacement for B\u0026amp;B Model 571-style black tank flusher check valves with standard 1\/2\" NPT threads.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: What pressure range can this valve handle?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: The valve is rated for typical RV water pressures between 8 and 125 PSI.\u003c\/p\u003e\n\u003c\/div\u003e\u003c\/section\u003e","brand":"Lisnhlin","offers":[{"title":"Default Title","offer_id":48084439695518,"sku":"B0CR4414BR","price":34.69,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0781\/2041\/9486\/files\/lisnhlin-front-view-check-valve.jpg?v=1785855346","url":"https:\/\/northtrailauto.ca\/products\/lisnhlin-rv-vacuum-breaker-check-valve-571-vac-chk-a-for-b-b-model-571-1-2-npt-prevents-black-tank-flush-backflow","provider":"North Trail Auto","version":"1.0","type":"link"}