A submersible pump primarily turns on and off by water pressure, which is controlled by a pressure switch.
Submersible pumps, particularly common in deep well applications, operate automatically using a control system. Unlike pumps located above ground, the pump motor and impellers are installed underground, submerged in the water source. The control mechanisms, however, are typically located above ground in a dry area for easy access.
The key component responsible for the automatic operation of many submersible well pumps is the pressure switch.
The Role of the Pressure Switch
As highlighted in the reference, the pump is turned on and off by water pressure, which is controlled by a pressure switch. This switch monitors the water pressure within the system, usually in a pressure tank. The pressure switch has two critical settings:
- Cut-in Pressure: The low-pressure threshold at which the pump needs to turn on.
- Cut-off Pressure: The high-pressure threshold at which the pump needs to turn off.
These settings create a pressure differential that ensures the pump cycles appropriately to maintain pressure in the system without running constantly.
The Automatic Cycle Explained
Here's a breakdown of how the pressure switch uses water pressure to control the pump:
-
Turning On:
- When water is used in the house (e.g., opening a tap, flushing a toilet), water is drawn from the pressure tank.
- This usage causes the water pressure in the system to drop.
- When the pressure falls below the cut-in pressure setting on the pressure switch, the switch closes an electrical contact.
- This sends power to the submersible pump motor located in the well.
- The pump turns on and starts pumping water from the well into the system and the pressure tank.
-
Turning Off:
- As the pump runs, it fills the pressure tank and increases the water pressure in the system.
- The pressure switch continuously monitors this increasing pressure.
- When the pressure reaches the cut-off pressure setting on the switch, the switch opens the electrical contact.
- This interrupts the power supply to the submersible pump.
- The pump turns off.
This cycle repeats automatically whenever the system pressure drops due to water usage, ensuring a consistent supply of pressurized water.
Understanding this simple, pressure-based control mechanism is fundamental to how many submersible well pump systems function reliably.
