Vac-Alert Model VA-2000L Lift Style.
Safety Vacuum Release System (SVRS) designed for suction lift applications (suction lift in this case applies to all applications where the circulating pump suction is either at or above the level of the pool water surface)
Incorporates a 0.170" diameter orifice opening installed below the surge tube section; this orifice opening is sized to prevent nuisance tripping of the SVRS unit caused by high vacuum surges typical of many pump start-up conditions
Utilizes a check valve assembly equipped with a 3.5 pound spring, a poppet disc, and a one-way (up only) vented poppet; this permits continued water flow to the circulating pump while the SVRS unit is in the open or vented position. The 3.5 pound spring, further compressed by the poppet disc, creates enough sealing force within the check valve to allow partial water flow to the circulating pump for suction lifts up to 3.5 feet. This is critical to the elimination of circulating pump damage that can be caused by a sustained dry-running condition. The one-way vented poppet allows the surge chamber to be internally recharged when the circulating pump is turned off.