Cash Acme 1/2 in. Vacuum Relief Valve with Dust Cover

The VR20 Vacuum Relief Valve is designed to protect hot water supply systems and pressure vessels against negative pressure. It is especially well suited for many domestic and commercial systems. It works by preventing internal vacuum conditions that could result in burned out heaters and/or collapsed storage tanks. Installed on the cold water supply line, the Cash Acme VR20 closes tightly under pressure and opens at a 1. mercury vacuum. Atmosphere admitted to the system breaks the vacuum, preventing collapse of the storage tank.|For protection of commercial hot water supply systems and pressure vessels against negative pressure|Prevents internal vacuum conditions|Opens quickly in emergency situations|Listed by CSA|Every valve is tested for performance prior to shipping|Guards against siphonage, burnt-out heaters and collapsing of storage tanks and negative pressure|Opens on a 1 in. mercury vacuum|Certified to ANSI Z21.22/CSA 4.4 and NSF/ANSI 372|Recommended that the VR20 be installed in an upright position|All brass body