The user can set the temperature in the range of 0-70 ℃. It is recommended to set the temperature in the range of 45-60 ℃. In order to make full use of free energy, photoelectric heating is designed to heat the whole barrel of water, and the temperature is as high as possible. However, the higher the water temperature is, the higher the air pressure in the barrel is, and the shorter the service life of the water tank is. When the water temperature reaches 75 ℃ ± At 5 ℃, the photoelectric heating is automatically cut off, and the bottom temperature drops to 60 ℃ ± The heater will start automatically at 5 ℃. According to the test, the water temperature of each person's shower needs 42 ℃, 40 ~ 50 liters of hot water, and the 150L water tank of photovoltaic energy water heater can continuously provide more than 3 people's shower at one time. But the normal shower time for three people should be one hour, so the hot water can be used by more people.