The Taco SR501-4 is a single-zone switching relay designed for efficient control of hydronic heating systems. This relay simplifies the wiring and control of circulator pumps, making it ideal for single-zone applications in residential and light commercial buildings. With an easy-to-read layout and LED indicators, it provides quick diagnostics and ensures reliable performance. https://www.partshnc.com/sr501-4-taco-1-zone-switching-relay