AQUATECH 0.7 gpm RO Demand Delivery Pump. **** PRODUCT MANUAL **** Demand activated (When pressure decreases). The basic demand pump is controlled by a built-in pressure sensing demand switch. When a faucet or valve is opened down stream of the pump, line pressure drops thus starting the pump automatically. Conversely, when the valve shuts, the line pressure increases turning the pump off automatically. The pressure switch actuates in response to the pump outlet pressure at a predetermined and preset pressure. The pump label indicates the pre-set OFF pressures. Typically, the OFF pressure is accurately set at the FACTORY and the ON pressure is within an allowable range below that value. In response to the characteristics of the system in which the pump is installed, such as the flexibility and length of the tubing, and the faucet or valves and the duration that they are open, these pressure settings may vary. Therefore, changes in pressure settings is expected with use and over time. If the pump does not have an integral pressure sensing demand switch (i.e. pump is operated with an external control), pump will be equipped with a bypass relief valve (bypass is factory preset).