The Model 78 Series pressure regulators are compact, lightweight, high-performance pressure reducing instruments. They are used primarily for supplying a stable source of air to process control equipment such as current to pneumatic transducers and control valve positioners.
Installation
Clean the lines thoroughly to remove all dirt, scale or other foreign matter before installing the regulator. Install with flow in direction of flow arrows on regulator body. The first should be installed with the drain cock facing down. Regulator should be installed as close as possible to a device utilizing the reduced pressure to minimize pressure drop. Do not use piping or tubing smaller than the regulator connections since this will restrict flow and reduce capacity. It is recommended that pressure gauges be installed on the inlet and outlet sides of the regulator as an aid in adjusting the pressure and in monitoring of working pressures.
Operation
Prior to applying supply pressure, loosen knob lock screw and turn pressure set knob counterclockwise. Turn on supply pressure. Output pressure should be zero. Slowly rotate set knob clockwise until desired pressure is reached. Tighten knob locking screw to ensure that pressure remains set at desired value. When changing output from a higher to lower pres¬sure, initially go to lower than desired pressure, then increase to desired pressure. Re-tighten knob lock-screw.
