Description & Operation: Programmer

This power servo unit mounted on heater case assembly has a reversible electric motor which operates the programmer disc vacuum switch, position sensor, location switch, limit switch, and vacuum valve. It also provides mechanical operation of the temperature door through an adjustable link. The programmer thus controls most of the electrical functions, and acts to operate the vacuum actuated doors and valves of the system in accordance with control lever operation and resulting positioning of the control head vacuum valve. See  CONTROL ASSEMBLY and Figureillustrations  .