The Viking Model H-1 Maintenance Air Compressor is an electric motor-driven, aircooled, single-stage, oil-less compressor. The unit is equipped with a check valve and provides a regulated (by pressure switch setting) and restricted (60 Cycle - 3.03 SCFM average free air from 0 to 40 psi gauge) or (50 Cycle - 2.50 SCFM average free air from 0 to 40 psi gauge) air supply. A pressure relief valve is factory installed to prevent pressurizing the system piping above 125 PSI (8.6 bar). The Model H-1 is for use when system pressures are required to be over 20 PSI (1.0 bar). The Viking Model H-1 Maintenance Air Compressor may be used to automatically maintain air pressure in a dry system after the system has been filled from a noncontinuous air supply. It may be used as a basic air supply for dry systems of 250 gallons (60 Hz) and 206 gallons (50 Hz) capacity or smaller.