2. A programmer in accordance with claim 1 wherein said auxiliary timer comprises a time wheel having a peripheral set of teeth and adapted to rotate through an angle which is proportional to the selected time interval, a driving lug which is integral with a moving system actuated by the motor means for driving the time wheel in a one-step movement corresponding to one of said teeth, an adjustable stop for fixing the origin of the angle which is proportional to the selected time interval and defining a zero position, a catch which is rigidly fixed to the time wheel for cooperating with said adjustable stop, a restoring spring for returning the time wheel against the adjustable stop, and a retaining pawl which is adapted to cooperate with the set of teeth of the time wheel so as to selectively prevent said wheel from being returned to its zero position, characterized in that on the one hand the catch of the time wheel of the auxiliary timer has a portion forming a cam adapted to engage and actuate a switching element on expiration of a time of interruption of the step-by-step rotary motion and the actuation of said swiTching element then permits the step-by-step pulses when said switching element has been selected by said cam at the moment when the electromagnetic means for stopping the step-by-step motion pulses has been activated by said switching element and that, on the other hand, the time wheel is provided at its periphery with a nontoothed zone for cooperating with the retaining pawl at a point beyond the tooth which corresponds to the expiration of the time interval in order to ensure that the time wheel returns to the same position after each stepwise rotational motion and that the rotation of said wheel does not continue beyond the set time interval if this interval is shorter than the time of heating or filling.

3. A programmer in accordance with claim 2, wherein the electromagnetic device comprises a moving armature, a lug which is integral with said moving armature and adapted to cooperate with an arm of the retaining pawl to disengage said retaining pawl from the time wheel when said electromagnetic device is activated to permit the step-by-step forward motion of the cams, and to engage said pawl with said time wheel when said electromagnetic device is deactivated to prevent the step-by-step forward motion of the cams.