Positive Head Systems 

A positive head system when sufficient pressure is available under gravity to provide a flow at the outlet. Typically a positive head condition exists where the flow from the outlet is more than 1 litre/min.

Negative Head Systems

A negative head system exists where there is inadequate pressure or head of water under gravity to provide sufficient flow at the outlet. Typically a negative head condition exists where the flow from the outlet is less than 1 litre / min.

Universal Pumps

Operate in positive or negative head conditions and do not require gravity flow to start, incorporating both a pressure and valve flow switch. The pump starts automatically when the pressure switch detects a drop in pressure when an outlet opens. The flow switch keeps the pump running whilst there is a sufficient flow of water. When the flow stops, the pump continues to run for three seconds allowing the system to repressure.