Water pressure switch italtecnica Italy 12 atm for water pumps. Available with rotating coupling.

Inside the pressure switch there are two springs with couplings. One large and one small.

• The large spring adjusts the starting pressure of the pump. The more we tighten the coupling, the higher this pressure becomes. It comes pre-set from the factory at 1.8 bar. This means that the pump will start operating when the water pressure is below 1.8 bar.
• The small spring adjusts the pressure differential. That is, the difference between the starting pressure of the pump and the stopping pressure. From the factory, this differential is set at 1.4 bar. This means that if our pump is set to start at 1.8 bar and the differential is 1.4 bar, then the pump will stop when the water pressure reaches 1.8 + 1.4 = 3.2 bar. The more we tighten the coupling of the small spring, the higher the pressure differential becomes.