Pedrollo FSG-2-D901 Pressure Switch with Dry Run Protection (1.4-2.8 Bar, 1-4) GRAY.

Pedrollo FSG-2-D901 is a reliable mechanical pressure switch with dry-run protection function, designed to prevent the pump from operating without water. It is intended for automatic pump control in water supply systems, where both stable operation and equipment protection against overload or failure due to lack of water are essential.

Functionality and Operating Principle

This pressure switch performs two key functions:

▪️Automatic pump start when pressure drops (e.g., when a tap is opened);
▪️Automatic pump stop when the preset upper pressure is reached or when water flow stops (dry-run protection triggered).

The device monitors water pressure in the system and closes or opens the pump’s power circuit when needed. This helps maintain constant pressure and prevents the pump from running dry.

Technical Specifications:

▪️Adjustable pressure range: from 1.4 to 4.6 bar
▪️Factory calibration: pump ON at 1.4 bar, pump OFF at 2.8 bar
▪️Maximum load current: 16 A
▪️Dry-run protection: yes
▪️Installation type: on the pipeline, with membrane in direct contact with water

Adjustment and Configuration

The switch can be manually adjusted via two springs, after disconnecting the pump from the power supply:

▪️Large spring (lower threshold — pump ON):
Turning the nut clockwise increases the activation pressure. One turn ≈ +1 bar.
To decrease — turn counterclockwise.

▪️Small spring (upper threshold — pump OFF):
Regulates the difference between ON and OFF (pressure delta). One turn ≈ ±0.2 bar.

▪️Startup procedure:

Make sure the system contains water.

Move the lever to the “START” position and hold for 1–3 seconds.

After starting, set it to “AUTO” mode.

For long shutdowns — switch the lever to “OFF”.

Advantages of Pedrollo FSG-2-D901

▪️Reliable protection of the electric pump from dry-run operation
▪️Simple manual pressure adjustment without special tools
▪️Suitable for borehole pumps, surface pumps, and pumping stations
▪️Operates in all clean water supply systems
▪️Factory-set precision with fine-tuning capability

The Pedrollo FSG-2-D901 pressure switch is the optimal solution for ensuring safe and stable pump operation. Its simplicity, versatility, and dry-run protection make it an essential component in automatic water supply systems for private homes, cottages, farms, and industrial facilities.