Substitute Value Operation
If an input potentiometer or sensor (or its circuit) fails, the control panel/module will ignore the faulty input and, in its place, use a replacement value which has been programmed into its memory for just this purpose. The replacement value, typically a mid-scale value for a particular input, allows the system to operate as normally as possible, despite the fault.
Substitute values for IHKA E36 components are:
- Desired temperature value (left or right)...............72°F (22°C)
- Interior temperature sensor..................................75°F (24°C)
- Heater core temperature sensor (left or right).......130°F (55°C)
- Evaporator temperature sensor...........................23°F (-5°C) ()
- Ambient temperature sensor..............................32°F (0°C)
| () | The substitute value for the evaporator temperature sensor is significantly below the A/C compressor cycling point (1-3°C). Therefore, if the evaporator temperature sensor signal is not plausible, the substitute value will switch the refrigeration system off. |