HVAC Control Systems: Heaters: Description: Notes

NOTE: Vacuum and wiring diagrams are of end of article.

All Ford Motor Co. heater systems are blend air systems. Outside air is drown into blower housing and is then directed either through or around heater core, mixed in plenum chamber and then discharged through defroster outlets, vent registers or floor ducts.

Discharge air temperature is determined by a temperature blend door which is controlled by a lever on control panel. Positioning of blend door determines what portion of incoming air is passed through heater core to be heated and then mixed in plenum chamber with heated air. Delivery of discharge air is directed by various doors to obtain a desired mode of operation. Doors may be operated either by a cable or a vacuum motor. In oil cases, cables and motors are controlled by either a Functional Lever or a Temperature Lever on the control panel.