Armstrong Series S Maintenance Free Circulator Pump This Armstrong In-Line circulator is suitable for hydronic heating and cooling, multi-stage zoning and general industrial service applications. It is built using a standard three-piece design that features a radially-split body, oversized shaft, centrifugal impeller, positive mechanical seal and modular construction. This circulator has been used by HVAC professionals for decades because it is cost-effective, durable and easy to...