Constant Pressure Systems / Variable Frequency Drives
Constant pressure systems are similar to conventional systems in that they require a pump, a pressure tank and a pressure switch or sensor. The pressure sensor monitors a system’s pressure and sends a signal to the control panel for the pump. A controller then signals the pump to perform at a rate required to maintain an optimized pressure and volume. The pressure setting may be adjusted at either the pressure sensor or motor controller depending on the system.
A pressure tank in a constant pressure system is typically much smaller than in a conventional system. In a constant pressure system, the tank stores very little water acting primarily as a buffer to prevent pressure fluctuations.
Pumps used in a constant pressure system are basically the same as those used in a conventional submersible system. The difference is the motor attached to the pump runs at variable speeds depending on water demand. The motor speed is controlled by a variable frequency drive controller. Depending on the specific system, the motor could be a single or three phase unit.
Benefits of a Constant Pressure System
- System maintains steady pressure instead of cycling with a 20 pound differential.
- Ideal for multiple uses, including sprinkler and drip irrigation systems.
- Requires a much smaller pressure tank, saving space in what typically is a confined mechanical room, pump house or pit.
- Soft starts and stops equating to less wear on the pump and motor. On units operating a three phase motor, wire size can be smaller which means less cost in applications when a pump depth is deep.