Search Tips
The CDT controls have built-in diagnostics which display error codes on the display. This section describes the codes.
| Display | Cause | Solution |
|---|---|---|
|
“E-4 CPU TOO HOT” |
Control board too hot; unit overheating or louvers clogged |
Turn switch to OFF position, then back to ON; if display still shows “E-4”, the PC board is getting too hot; clean louvers and check cooling fan; if cooling fan is not working, have it replaced; once panel cools down, the controls should return to normal; if “E-4” persists, have the PC board replaced |
| “E-5 AIR TEMP TOO HOT” | Faulty relay, PC board, or air probe | Turn switch to OFF position, then back to ON; if display shows “E-5”, the heating circuits and temperature probe should be checked; once the unit cools down, the controls should return to normal; if “E-5” persists, have the PC board replaced |
| "E-6B AIR TEMP SENSOR FAILED SHORTED" | Faulty air temperature probe | Turn switch to OFF position, then back to ON; if the display shows “E-6”, the temperature probe should be checked; once the temperature probe is repaired, or replaced, the controls should return to normal; if “E-6”persists, have PC board replaced |
| "E-41 SYSTEM DATA LOST" | Memory scrambled | Turn switch to OFF position, then back to ON; if the display shows “E-41”, the control should be re-initialized (see Programming Section); if “E-41” persists, have PC board replaced |
|
"E-50" |
RAM Failure |
Turn switch to OFF position, then back to ON; if “E-50” reappears, have control board replaced |
| "E-51" | NOVRAM Failure | Turn switch to OFF position, then bakc to ON; if “E-51” reappears, have control board replaced |
| "E-53" | EPROM Failure | Turn switch to OFf position, then bakc to ON; if “E-53” reappears, have control board replaced |
