1.From the perspective of domestic hot water sanitation and preventing bacterial growth, the minimum storage temperature of the water tank should not be lower than 50 degrees, preferably 55 or 60 degrees. If the water temperature is set very low, 45 degrees or 40 degrees, it will cause the hot water to breed bacteria, and the system must take special sterilization measures: some models of boilers have a hot water sterilization function, and the water tank is regularly heated to more than 60 degrees. And maintain for a period of time to kill bacteria. (The boiler function must be turned on)   2. even if we turn on the hot water sterilization function of the boiler, we still do not recommend setting the water temperature of the water tank very low for several reasons: If the temperature is set too low, due to the low temperature of the stored water, the water supply capacity of the water tank will decrease to a certain extent, and the ability to cope with a large amount of water consumption in a short time will decrease.   A. For most boilers, the default outlet water temperature of the boiler when heating the water tank is based on the set temperature of the water tank, usually the set temperature of the water tank +15°C. If the water tank is set to 45°C, then the boiler outlet water temperature is only 60°C. At this time, the heat exchange capacity of the water tank will decrease due to the drop in the temperature of the boiler outlet water, which will affect the heat exchange capacity of the boiler outlet water to the domestic hot water in the water tank, resulting in a significant drop in the ability of the water tank to continuously supply water for a long time.   B. Since the heat exchange capacity of the water tank is affected by the lower boiler outlet water temperature, if the heat exchange capacity is lower than the minimum power of the boiler, it will cause the boiler to start and stop frequently.   Based on the above reasons, we recommend that the temperature of the water tank should be set at 50-60 °C.   It is recommended that the boiler can be used with ETOP's thermostat, and the temperature and time can be programmed thermostat to make life easier