Automatic maintenance of water level in the tank

Automatic maintenance of water level in the tank
Pump control circuit with galvanic isolation of input and output
Purchased water level sensors are used. Reliable. Automatically supports
specified water level. Collected and used at the dacha.
Description of work.
If the water level is below both sensors, DD1.4 will appear on pin 11 of the DD1.4 chip.
a logical unit and triac VS2 will turn on the pump. With a gradual increase in water level
even if water comes into contact with the lower sensor, there will still be
logical unit. As soon as the water level reaches the upper sensor at pin 11
chip DD1.4 will appear logical zero, triac VS2 will turn off the pump and water in
container will not be supplied. When the water level drops and the upper sensor will not be
comes into contact with water, then pin 11 of the DD1.4 chip will still be logical zero
and the pump will not turn on. But if the water level drops below the lower sensor, then
11 pin of the DD1.4 chip will appear and the pump will turn on. Pump power no more than 2 kW.
The triac is installed on the radiator. The radiator area depends on the pump power.
Printed circuit boards (power and control)
The power board and triac are installed on the radiator