Description: Do not heat sea water or salt water The built-in circulating water pump control system（Stop working after reaching the temperature, then every 15 minutes the circulating water pump circulates to check the water temperature and turns on after it is lower than the set temperature.）,energy efficient, does not require additional installation of circulating water pump switch and control equipment, which greatly simplifies the installation and use of the circulating system, saves the use and installation costs, and ensures the safe use of the thermostat.ST series pool heaters are special used for small pool less than 15CBM, massage pool and hot spring to heat and keep warm; Meanwhile, can be a assistant for heat pump in heating. This product adopts latest constant temperature controller, temperature sensor replaces traditional magnetic flow switch, it improves greatly of trouble free in working time, adaptability of water environment and stability Features: Manual reset temperature control switch:Once unexpected high temperature 60℃ occurs, the temperature switch cuts off the system. You need to cut off the main power supply, resolve the fault and wait the temperature to fall below normal temperature, then press the ‘Reset’ button to restart the heater Unique control system: ST series are the newest generation with our unique control system. With this advanced control system, the traditional mechanical water flow sensor is replaced by modern digital temperature sensor, and the features of the temperature Sensor technique are: A. The flow-temperature sensor is always under the control of software, accurately monitoring the temperature status of the whole system, and then adjust the settings to maintain the water temperature and protect the heater from unexpected situations B. No mechanical sensors, avoid any mechanical failure to affect the function of the heater C. Avoid affection of ion accumulation to mechanical sensors D. Greatly reduce unnecessary circulation cycles, prolong the life of circulation pumps and save more energy Intelligent self-diagnose function: The control system keeps on monitoring the running status of every parts of the heater, and quickly reacts and displays corresponding hint message for any incident, so as to avoid any damage or malfunction happens If any fault happens, the heater is stopped immediately