HVACopediaMidea · Mini-split
ODU Ed Adapter / inverter board to main board communication error
What the control is telling you
48K high heat only: the outdoor main board gets no reply from the adapter (inverter) board.
Applies to: DLCMRBH / DLCMHBH multi-zone outdoor units 18-48K (Midea, Carrier, Viessmann Vitocal 200-S)
Test and repair steps
- Safety kill power at the disconnect and wait for the inverter capacitors to discharge before touching boards or wiring.
- Restart after 3 minutes.
- Check the wiring and plugs between the boards.
- Still there replace the adapter board, then the outdoor main control board.
Models that show this code
7 models in Midea DLCM(R/H)B multi-zone outdoor
Other codes on the same units
- ODU E4 Outdoor or T2B sensor fault (outdoor board)
- ODU E5 Over or under voltage (outdoor board)
- ODU E6 PFC module protection (outdoor board)
- ODU E8 Outdoor fan speed fault (outdoor board)
- ODU F1 Zone A coil outlet sensor (T2B-A) fault
- ODU F2 Zone B coil outlet sensor (T2B-B) fault
- ODU F3 Zone C coil outlet sensor (T2B-C) fault
- ODU F4 Zone D coil outlet sensor (T2B-D) fault
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Source: DLCMRBH/DLCMHBH Multi-Zone Outdoor Service Manual (sold as Midea, Carrier and Viessmann Vitocal 200-S; Viessmann doc 6225551-03, 12/2024), Table 27 Outdoor Unit Digital Codes p.32; diagnosis p.72. Summarized in our own words; check the original manual for your model.
Homeowner looking at this code? See what it means for you and when to call a technician.
For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.