The instrument number of solar water heater shows the water temperature and water level. Fully automatic water level control, alarm when the water level is lower than the specified value and automatically replenish water, and automatically stop replenishing water when the specified water level is reached (the upper limit of water level can be set by the user. The set parameters have power-off protection, so users don't need to set them again when they are powered on again); When the water level is between the high and low water levels, you can manually supply water and stop water by touching the button; When the water pressure is insufficient, the booster pump is automatically controlled to work to avoid water supply failure caused by insufficient water pressure; Automatic temperature control can prevent moisture from entering after high temperature air drying, and can prevent the vacuum tube from bursting due to sudden injection of cold water. There are solar control instruments or microcomputer control instruments and controllers.