When sourcing these controllers, prioritize the Temperature Difference Range (Delta T) and Measurement Accuracy. For solar thermal systems, a controller should support a range of 0.1°C to 50°C with an accuracy of ±0.5°C. Ensure the device includes High-Temperature Protection for collectors and Anti-Freeze Functions for circulation pipes. Additionally, verify the Sensor Type compatibility, typically PT1000 for high-temperature collectors and NTC 10K for tank storage, to ensure precise data acquisition.