The weather of solar water heater is below zero. Do you want to add water or drain?

When the weather of solar water heater is cold in winter and the temperature is below zero, the water in the water heater must be discharged to prevent the heating pipe of the water heater from freezing and cracking.

This is because there is still air in the water storage tank and solar heating pipe after the water is pumped dry by solar energy. Without water, it won't freeze, and water won't increase in volume and crack the water pipe because of freezing. The solar heating tube is connected with the water storage tank, and the air in the solar heating tube expands with heat and contracts with cold, which is not enough to rupture the heating tube. Therefore, discharging water from solar energy can prevent solar energy from freezing and cracking.