Glossary of Terms - "B"
The water pressure (usually expressed as pounds-per-square-inch - P.S.I.) of the system into which the chlorine solution is being injected. The water pressure of the water supply line must be greater than this back pressure. A differential of 40 P.S.I. to 140 P.S.I. is typical, depending on the specific water system needs and available equipment.
A mechanical device (usually a centrifugal or turbine pump) that boosts the water pressure of the water supply line over that of the back pressure.