Solar water heaters have gained widespread popularity in China, particularly in rural areas, thanks to their performance and low operational costs. These heaters produce water at very high temperatures, even reaching boiling point in summer, which accelerates the buildup of scale inside the tanks. This scale not only affects the normal operation of the solar water heaters but also poses serious health risks to users.

Causes of Scale Formation:

One: As the water inside the solar water heater is continuously heated and evaporated, it becomes increasingly concentrated, leading to a higher concentration of calcium, magnesium, and salts. When this concentration exceeds their solubility limits, they precipitate out of the water, forming sediment.

Heating water causes the bicarbonates to decompose, resulting in insoluble precipitates.

As temperatures rise, the solubility of certain salts gradually decreases and they precipitate. Impurities in tap water, as well as dirt formed from the death of microorganisms from long-term use of solar energy, can lead to the formation of scale. These precipitates, impurities, and dirt adhere to the vacuum tube walls, creating insoluble scale.

The Dangers of Scale Build-up:

One: Decrease heating efficiency. The low thermal conductivity of scale causes it to adhere to the internal surface of the heat collector, preventing the absorbed heat from being promptly transferred to the water, thereby increasing the heating time.

Scale deposits have a certain degree of corrosiveness, which can corrode the water tank, damage the insulation effect, and even lead to leaks in the water tank.

Scaling can harm human skin, cause hair follicle blockages, and lead to various skin diseases. Scaling also contains harmful substances like nitrates and nitrites, which can cause cancer.

Descaling Method:

Discharge the water from the solar water tank.

Unfold all the vacuum tubes and use a long wooden stick, with one end tightly wrapped in a ball of cotton. The cotton ball should be slightly larger than the inner diameter of the vacuum tube but not too big; just a little resistance should suffice. Gently push the cotton ball into the vacuum tube and repeat this action multiple times. Finally, rinse with clean water.

Thirdly, open the inlet and outlet of the solar water heater, pour the descaling agent into the water tank.

Step 4: Activate the automatic hot recirculation for 20-30 minutes to ensure the descaling solution thoroughly contacts all parts of the water tank.

Five: Open the drain outlet and flush out the cleaning agent.

Fill the water tank to capacity and then automatically heat circulate for 5 minutes.

Step 7: Drain the water from the storage tank, close the drain valve, install the vacuum tube, and the maintenance and descaling of the solar water heater is complete.