The pressure gauge allows direct reading of the pressure, and thus allows precise adjustment of the pressure reducing valve to local installation conditions,Pressure Gauges for sprinkler systems and fire pumps are designed for use with air or water,These gauges are usually of the Bourdon tube type,The moving parts are fabricated with appropriate corrosion-resistant materials,These gauges are calibrated with a hydraulic testing unit by adjusting the dial pointer to read correctly at known pressures.