Solar Water Heater Controller Sr81 (Sr868C8) 100240V Overview A dedicated temperature and thermal controller designed for solar water heating systems. The Sr81 (Sr868C8) controller provides reliable regulation of collector and storage temperatures across a wide input voltage range, making it suitable for many residential and light commercial solar hot water applications. Key benefits Precise temperature management: Monitors temperatures and controls system operation to maintain target water temperatures and prevent overheating. Wide voltage compatibility: Operates on 100240V supply, allowing use with a broad range of electrical installations. Simplifies system operation: Automates pump or valve activation based on temperature differentials to reduce manual intervention. Modelcompatible replacement: Matches functionality of controllers labeled Sr81 or Sr868C8 for straightforward replacement or integration. Core functions Temperature control for solar collectors and storage tanks. Thermal regulation to activate circulation pumps or control valves when preset temperature differences are reached. Protects systems from excessive collector temperatures by stopping circulation when required. Compatibility and installation Designed for solar water heating systems that accept Sr81 or Sr868C8 style controllers. Works with standard 100240V electrical supplies; verify local installation requirements and wiring before fitting. Intended for system integration where automated pump or valve control is required based on temperature readings. Performance and reliability Provides stable thermal control to help maintain consistent hot water availability. Built to operate across a wide voltage range for flexible deployment in different electrical environments. Use in appropriately rated enclosures and wiring installations to ensure safe, longterm operation. Practical use scenarios 1) Residential solar hot water system: Install as the primary controller to activate a circulation pump when the roof collector is hotter than the storage tank, improving system efficiency and reducing manual oversight. 2) Small commercial setups: Use in smallscale commercial or multifamily hot water systems to automate temperaturedriven circulation and avoid overheating during peak sun periods. 3) Controller replacement or retrofit: a worn or incompatible controller labeled Sr81 or Sr868C8 to restore automatic temperaturebased control without major system changes. What to check before Confirm that the Sr81 or Sr868C8 controller format and terminal functions match your system wiring. Verify the electrical supply is within the 100240V range. Confirm sensor types and wiring conventions used in your system are compatible with this controller model. Specifications Model: Sr81 (Sr868C8) Function: Solar water heater temperature and thermal controller Voltage: 100240V This controller is a practical option for systems requiring reliable temperaturebased control and broad voltage compatibility. Verify installation details and wiring compatibility with your solar water heating system prior to installation.