The Resideo L4081A1023 SPST High/Low Limit Aquastat Controller is a multifunction temperature control designed for hydronic HVAC systems. It monitors water temperature and opens or closes the circuit at adjustable high and low setpoints to regulate system operation. Commonly used in boilers, water heaters, and hydronic heating applications, this controller helps maintain stable temper... https://www.partshnc.com/l4081a1023-resideo-dual-aquastat-horizontal-mount