How to fill water into boiler

The heating system is a system that works with closed circuit water circulation. When the water pressure in the system falls below 1 bar, the boiler does not work or when it exceeds 3 bar, the boiler gives the water out.

When the water pressure falls below a bar, it fills water through a small valve under the boiler (not the valves connected to the pipes, but connected to the boiler body). Water is given to the system by opening the valve and the pressure value on the boiler is flooded until it reaches the range of 1.5-22 bar. The boiler flood valve is a valve that is usually a small plastic title in a position that can be easily reached by hand just below the boiler.

Usually the blue is a small piece, when it turns it, the clock in the front panel turns the clock in the part. 2 is normal.