With the modulating feed water system, the level in the boiler is continuously adjusted by a PID regulator that controls the opening of a modulating valve downstream of the pumps to supply maintained always in function.

The water level in the generator is continuously detected by a capacitive probe, inserted in a calm barrel. The 4-20mA analog signal is transmitted to the electrical panel where an electronic controller elaborates the signal in Proportional Integral Derivative.

Using the thresholds suitably set up the controller provides the on/off output for the automatic starting and stopping of the supply pumps and an analog signal 4-20mA for adjusting the opening of the modulating valve.

The modulating valve is equipped with a handwheel for the emergency manual opening or closing and is open in the absence of signal, to allow a correct water supply in the generator even in the presence of any anomalies.