A manifold system is provided herein. The manifold is operative to automatically switch between an In-Use supply of compressed gas to a Reserve supply of compressed gas. The manifold system is constructed so that after it has been installed, it may be converted for use in other applications such as between compressed gas cylinders and portable bulk liquefied gas. The system may include low wattage electric heater which are mechanically held in direct contact with the valve seat body housing of the primary regulators. The direct contact of the heaters with the valve seat is operative to prevent the primary regulator valve seat from freezing up. The manifold system may include transducers at a plurality of points in the system. A processor is operative to control one or more solenoids to switch supplies of compressed gas and to trigger alarms responsive to the outputs of the transducers.