Loading cycle of a boiler with one level probe: The loading function regulates and controls the correct level of water in the boiler.

If the level probe in not covered by water, then the pump and solenoid valve output are simultaneously activated. When   the probe is reached by water, the pump and solenoid valve output are deactivated and remain switched off until the status of the probe changes again. The loading function remains activated for a maximum of 150 seconds (so called time-out). After this period of time the pump and solenoid valve outputs are deactivated in order to protect the machine from eventual breaks or malfunctioning.

Moreover there is a push button, every time it is switched on, the pump and solenoid valve are activated since the status of the button is off.