The Johnson G-7185 Pneumatic Step Controller is designed to regulate electric heating elements in accordance with the demands of a direct acting, single or dual temperature pneumatic thermostat. The G-7185 is available with six or nine pressure electric switches adjusted for sequence operation within a nominal operating range of pilot pressure. Each switch is rated at 20 amperes 480 volts A.C. (non-inductive); 360 V.A., 120-480 volts A.C. pilot duty. The G-7185 is U.L. component recognized. The solenoid operated exhaust valve and a reverse acting 2:1 cumulator are integral parts of the G-7185 and act as fail safe devices. If a power failure occurs in the fan circuit, the solenoid valve exhausts the control air from the switches returning them to their normally open position. For unit ventilator applications, 120 volts A.C. six or nine point models are available with a line cord and plug and 1/8 in. brass barbed fittings for supply and pilot pressure connections.