A deicer control system for a pneumatic deicer wherein a solenoid operated valve directs either pressurized air or creates and pulls a vacuum on the inlet port of a control valve. The inlet port communicates to an outlet port in the control valve post moveable piston which in one position maintains communication between the ports and in a second position is operative to block communication between the ports. The piston has one face of the piston with two distinct effective surface areas, wherein one surface area communicates at all times with the inlet port and upon a predetermined force on such one surface area such piston is moved to expose both effective surface areas and block communication between the inlet port and the outlet ports of the control valve.
