Unloader Valve

A pressure-sensitive unloader is used as a primary pressure control device to set and maintain consistent system pressure while providing an energy and system savings feature that allows the pump to run at low pressure when the downstream flow shuts off. An unloader contains a check valve that traps pressure between the closed downstream device (shut-off gun) and the unloader, causing an internal piston to open, allowing the pump to unload at low pressure. When the shut-off gun is opened back up, the system will return to operating pressure.